BI TP QUN TR SN XUT

HACH NH LCH TRNH SN XUT Bi 1: Cng ty Cy xanh xem li 5 hp ng va k kt vi khch hng v xy dng v vn hoa sau y.

Hp ng Thi gian xy dng( ngy) Thi gian (ngy) A 3 8 B 2 4 C 5 6 D 1 12 E 9 7

Hy tnh: 1/ Dng thi gian trung bnh, s Cng vic chm tr v s ngy chm tr trung bnh theo nguyn tc thi gian thi cng ngn nht SPT. 2/ Cc s liu i vi 3 thng s trn theo nguyn tc thi hn sm nht EDD. 3/ Nn khuyn cng ty iu nh th no? Bi Gii 1 1/ Theo phng php SPT:

Hp ng Thi gian xy dng

Thi gian bn giao

Thi gian han thnh

S ngy tr

D 1 Ngy th 12 Ngy th 1 0 B 2 Ngy th 4 Ngy th 3 0 A 3 Ngy th 8 Ngy th 6 0 C 5 Ngy th 6 Ngy th 11 5 E 9 Ngy th 7 Ngy th 20 13

Tng cng 20 41 18

- Dng thi gian trung bnh: ngy2,8541 =

- Cng vic b tr: C tr6 5 ngy v E tr 13 ngy - S ngy tr bnh qun 18:5= 3,6 ngy ( cho mi cng vic) 2/ Theo phng php EDD:

Hp ng Thi gian xy dng

Thi gian bn giao

Thi im han thnh

S ngy tr

B 2 Ngy th 4 Ngy th 2 0 C 5 Ngy th 6 Ngy th 7 1

E 9 Ngy th 7 Ngy th 16 9 A 3 Ngy th 8 Ngy th 19 11 D 1 Ngy th 12 Ngy th 20 8 20 64 29

-Dng thi gian trung bnh 64/5= 12,5 ngy -c 4 hp ng tr c: 1 ngy;E :9 ngy ;A; 11 ngy; D; 8 ngy

- S ngy tr bnh qun : chongy(8,5529 = 1 cng vic)

3/ Cng ty cy xanh nn iu theo phng php SPT v: -S thi gian cn cho 1 cng vic t hn -S cng vic chm tr t hn phng php EDD (2

-Dng thi gian trung bnh : ngy5,344

137 = -S ngy tr trung bnh 34/4= 8,5 ngy -S cng vic chm tr : 3 cng vic b) Theo phng php EDD: Hp ng Thi gian thc

hin Thi im giao hng

Thi im han thnh

S ngy tr

C 12 Ngy th 18 Ngy th 12 0 A 10 Ngy th 22 Ngy th 22 0 D 18 Ngy th 30 Ngy th 40 10 B 25 Ngy th 45 Ngy th 65 20 65 30 -Dng thi gian trung bnh: 139/4=34,75 ngy -S ngy tr trung bnh 34/4 =7,5 ngy - s cng vic chm tr : 2Cng vic ( Hai phng php cn li FCFS v LPT thng khng cho chng ta thi gian trung bnh nh.Cng nh s ngy tr trung bnh cho mi cng vic rt ln nn chng ta khng xt n) Qua 2 phng php trn chng ta c nhn xt

- Phng php SPT cho ta dng thi gian trung bnh nh. - Phng php EDD cho ta s ngy chm tr trung bnh nh nht - Phng php EDD cho ta s cng vic t tr nht..

Bi 3 T hp xy dng qun G vp nhn c 6 Hp ng xy nh sau y

Nh Thi gian xy ct(ngy) Thi gian (ngy) A 6 22 B 12 14 C 14 30 D 2 18 E 10 25 F 4 34

Gia 2 cch iu theo nguyn tc n trc lm trc FCFS v nguyn tc thi hn sm nht EDD bn khuyn T hp nn dng cch no ?Ti sao? Bi gii: a/ Nguyn tc FCFS: Cng vic xy nh

Thi gian xy ct

Thi gian nghim thu

Thi gian han thnh

S ngy chm tr

A 6 22 Ngy th 6 0 B 12 14 Ngy th 18 4

C 14 30 Ngy th 32 2 D 2 18 Ngy th 34 16 E 10 25 Ngy th 44 19 F 4 34 Ngy th 48 14 48 182 55 -Dng thi gian trung bnh cho 1 nh 182/6=30,33 ngy -S ngy tr bnh qun cho 1 nh 55/6= 9,16 ngy b) Theo nguyn tc EDD: Cng vic xy nh

Thi gian xy ct

Thi gian nghim thu

Thi gian han thnh

S ngy tr

B 12 14 Ngy th 12 0 D 2 18 Ngy th 14 0 A 6 22 Ngy th 20 0 E 10 25 Ngy th 30 5 C 14 30 Ngy th 44 14 F 4 34 Ngy th 48 14 48 168 33 -Dng thi gian bnh qun cho 1 nh 168/6m =28 ngy -S ngy tr bnh qun 1 nh 33/6 = 5,5 ngy Theo 2 phng php iu trn chng ta dng phng ohp EDD tt hn v s bnh qun cho 1 nh t hn, s ngy tr t hn, v s nh tr cng t hn. Bi 4: T hp xy dng nh Qun G vp nhn c 6 Hp ng xy nh sau y. H mun xem xt nguyn tc thi gian thi cng ngn nht SPT v thi gian thi cng di nht LPT. Vy bn tnh tan v cho li khuyn. Nh Thi gian xy ct Thi gian ( ngy) A 6 22 B 12 14 C 14 30 D 2 18 E 10 25 F 4 34 Bi gii4:

a) Nguyn tc SPT Cng vic xy nh

Thi gian xy ct

Thi gian han thnh

S ngy tr C

D 2 Ngy th 18 Ngy th 2 0 F 4 Ngy th 34 Ngy th 6 0

A 6 Ngy th 22 Ngy th 12 0 E 10 Ngy th 25 Ngy th 22 0 B 12 Ngy th 14 Ngy th 34 20 C 14 Ngy th 30 Ngy th 48 19 48 124 38 -Dng thi gian bnh qun cho 1 nh 124/6=20,33 ngy -S ngy tr bnh qun cho 1 nh : 38/6 = 6,33 ngy Theo phng php ny thi gian bnh qun thc hin xy 1 nh l thp nht do kinh t nht

b) Nguyn tc LPT: Cng vic xy nh

Thi gian xy ct

Thi gian nghim thu

Thi gian han thnh

S ngy tr

C 14 Ngy th 30 Ngy th 14 0 B 12 Ngy th 14 Ngy th 26 12 E 10 Ngy th 25 Ngy th 36 11 A 6 Ngy th 22 Ngy th 42 20 F 4 Ngy th 34 Ngy th 46 12 D 2 Ngy th 48 Ngy th 48 30 48 85 -Dng thi gian trung bnh cho 1 nh 212/6= 35,33 ngy -S ngy tr bnh qun cho 1 nh 85/6 =14,16 Theo phng php LPT thi gian bnh qun xy 1 nh ln nht , s ngy tr l nhiu nht.Do T hp xy dng nh G vp nn chn phng php SPT s tt hn. Bi 5 Hy dng nguyn tc Johnson xc nh th t gia cng ti u cho cc cng vic lm trn hai my sau y: Cng vic My I My II A 6 12 B 3 7 C 18 9 D 15 14 E 16 8 F 10 15 Bi gii 5: Bc 1 Xp th t cc cng vic theo th t thi gian Min tng dn

Cng vic My I My II B 3 7 A 6 12 E 16 8

F 10 15 C 18 9 D 15 14

Bc 2 Sp xp theo nguyn tc Johnson: May I My II

Bc 3: V s cc cng vic B=3 A=6 F=10 D=15 C=18 E=16 B=7 A=12 F=15 D=14 C=9 E=8

B A F D C E 3 6 10 15 18 16 7 12 15 14 9 8

10 37 52 68 76 Vy Tng thi gian thc hin trn 2 my nh nht l: TMin=76 g Bi 6: Cc Cng vic tun t c lm vic trn 2 my cho trong bng sau y;thi gian gia cng c tnh bng gi.Hy lp bng iu gia cng sao cho khan thi gian gia cng l nh nht. Cng vic My I My II V 7 8 W 7 6 X 2 1 Y 5 9 Z 8 4 Bi gii 6: Bc 1 : Xp cng vic theo th t thi gian Min tng dn. Cng vic My I My II X 2 1 Z 8 4 W 7 6 Y 5 9 V 7 8 Bc 2: Sp xp theo nguyn tc Johnson

Y V W Z X My I :5 7 7 8 2 My II: 9 8 6 4 1

Bc 3: V s thc hin cc cng vic trn 2 my: Y=5 V=7 W=7 Z=8 X=2 Y=9 V=8 W=6 Z=4 X=1 14 22 28 32 33 Tng thi gian lm vic trn 2 my nh nht Tmin= 33 gi

HACH NH CHIN LC TNG HP

Bi 7 Nh my Cao su HB c lp bng d bo nhu cu hng thng v lp xe HonDa v cc chi ph c cho nh sau: Thng Nhu cu S ngy sn xut Nhu cu mi ngy 1 900 22 41 2 700 18 39 3 800 21 38 4 1200 21 57 5 1500 22 68 6 1100 20 55 6200 124 -Chi ph tn tr 1000/n v /thng -Chi ph hp ng ph 10.000/n v -Chi ph lm ngai gi 7.000 /gi -Mc lng trung bnh 5.000 /gi ( 40.000 /ngy) -S gi cng sn xut 1 sn phm l 1,6 gi/n v -Chi ph o to 10.000 /n v -Chi ph sa thi 15.000 /n v Nu mun gi lc lng cng nhn l 8 ngi sn xut n nh, thu th cho sn xut vt gi. Hy tnh chi ph ca chin lc? Bi gii 7:

-Mc sn xut mi ngy : 8 ngi x ngySP /406,1

8 = -So snh gia mc sn xut v nhu cu ta c bng sau: Thng Nhu cu Mc sn xut Tn kho 1 1 900 40x22=880 0 20

2 700 40x18=720 20 3 800 40x21=840 60 4 1200 40x21=840 0 300 5 1500 40x22=880 0 620 6 1100 40x20=800 0 300 6200 80 1240

1. Chi ph sn xut trong gi: 8 ngi x 40.000 x 124 ngy = 39.680.000

2. Chi ph sn xut ngai gi: 1240 x 7000 x 1,6 gi = 13.440.000 3. Chi ph tn kho: 80 x1000 = 140.000 Tng chi ph ca chin lc: = 53.260.000 Bi 8: Nh my Cao su tin li sn xut lp xe hi c s liu v sn phm ca mnh nh sau:

- Kh nng sn xut trong gi c 2600 n v /giai an. - Chi ph lm trong gi l 10.000 /n v - Chi ph lm thm ngai gi l 12.000 n v - Chi ph tn kho l 2.000 /n v/giai an ( da vo tn kho cui k) - Chi ph o to 5.000 /n v - Chi ph sa thi 10.000 /n v - Chi ph thiu hng l 5.000/n v/giai an - Tn kho u k l 400 n v

Giai an Nhu cu 1 4000 2 3200 3 2000 4 2800

Hy lp bng k hach sn xut lm sao cho khng c tn kho cui k giai an 4. Chi ph chung cho k hach ny l bao nhiu?

Bi gii 8: Chin lc 1:

Giai an Nhu cu Sn xut Tn kho u k

Tn kho cui k

Sn xut vt gi

1 4000 2600 400 - 10002 3200 2600 - 6003 2000 2600 - +600 4 2800 2200 - 0 12600 10.000 400 600 1600

Chi ph chung ca chin lc:

- Sn xut trong gi: (2600 x3 +2200 x1) x 10000 = 100.000.000 - Chi ph sn xut vt gi 1600 x 12.000 = 19.200.000 - Chi ph tn kho : 600 n v x2.000 /n v = 4.000.000 - Chi ph sa thi /2600-2200) x10.000 /n v = 4.000.000

Tng chi ph ca chin lc 1 = 124.400.000 Chin lc 2:

Giai an Nhu cu Sn xut Tn kho u k

Tn kho cui k

SX vt gi

1 4000 2600 100 400 - 2 3200 2600 -600 - - 3 2000 2000 - - 4 2800 2600 -200 - -

Chi ph chung ca chin lc: - Chi ph SX: (2600 x 3 +200) x 10.000 = 98.000.000 - Chi ph thiu hng : 1800 x 5000 = 9.000.000 - Chi ph sa thi (2600 -2000) x 10.000 = 6.000.000 - Chi ph o to (2600 -2000) x 5.000 = 3.000.000 Tng chi ph ca chin lc 2 = 116.000.000

QUN TR HNG TN KHO

Bi 9: Nh my Xi mng H tin c nhu cu v nguyn liu Clinke l 1000 tn/nm. Chi ph t hng mi ln l 100.000 /n hng. Ph tr hng 5000/tn/nm ;gi s trong nm lm vic 300 ngy. Hy xc nh a/Lng mua vo ti u mi ln t hng ? b/s lng n hng mong mun? c/ khan cch thi gian gia 2 n hng? d/Tng chi ph v tn kho l bao nhiu? Bi gii 9:

a/Sn lng ti u mi ln t hng l:HDS2 = t200

5000100000.1000.2 =

b/ s lng n hng mong mun : N=D/Q =100/200 = 5 n hng/nm c/Khang cch thi gian gia 2 n hng: T= 300/5 = 60 ngy d/ Tng chi ph v tn kho: TC= Ch+Ctt

TC = HQSQD

2+

TC= 000.000.150002

200000.1002

1000 =+

Bi 10: Cng ty Phng Hang chuyn Mua bn chi my bay tr em. Gn y H c i tc p dng chnh sch khu tr theo sn lng n hng c th nh sau :

- Gi thng thng 1 chic my bay l 5 USD - Vi sn lng mua t 1000 -> 1999 chic gi l 4,8 USD - Vi sn lng mua trn 2000 gi l 4,75 USD. - Chi ph t hng l 49 USD 1 ln t hng. Nhu cu hng nm l 5.000 chic my

bay. Chi ph thc hin tn kho bng 20% gi mua 1 n v hng. Vy sn lng hng ti u m cng ty Phng Hang cn phi thc hin l bao nhiu?

Bi gii 10: Bc 1 : Xc nh Q* theo cc mc gi khu tr

Q*1= .5.2,0

49.5000.2 =700 chic /n hng

Q*2= .8,4.2,049.5000.2 = 714 chic /n hng

Q*3 = .75,4.2,049.5000.2 = 718 chic /n hng

Bc 2: iu chnh Q*

- Vi Q* tnh gi 5 USD nm trong khan 0 ->999 nn khng cn iu chnh. - Vi Q* tnh gi 4,8 USD l 714 thp hn dy khu tr 1000 -> 1999 do phi

iu chnh ln con s ti thiu 1000. - Vi Q* tnh vi gi 4,75 USD l 718 thp hn dy khu tr 2000 tr ln , do

phi iu chnh ln mc ti thiu l 2000. Tm li sau khi iu chnh chng ta c:

- Q1*= 700 ; Q2*=1000 ; Q3*= 2000 Bc 3 Xc nh tng chi ph ca hng tn kho

Mc khu tr

Gi n v Q* Chi ph mua hng

Chi ph t hng

Chi ph tn tr

Tng chi ph

1 5 700 25.000 350 350 25.700 2 4,8 1000 24.000 245 480 24725 3 4,75 2000 23.750 122,5 950 24.822,5

Bi 11 Cng ty Dc phm vnh pht chuyn bn 1 lai dc c nhu cu hng nm v lai sn phm ny l 8000 n v , chi ph mua sn phm ny l 1000 /n v. Chi ph thc hin

tn kho b8ng 4% so vi gi mua. Chi ph t hng l 20.000 /n hng. Hng c cung cp lm nhiu chuyn v cn 8 ngy nhn hng k t ngy t hng.Nhu cu bn ra mi tun l 96 n v ( mi tun lm vic 6 ngy , mt nm lm vic 250 ngy). Hy tnh: 1/ Lng t hng ti u l bao nhiu? 2/ im t hng li? 3/ Tng chi ph v hng tn kho l bao nhiu? 4/ S ln t hng ti u trong nm ? 5/ S ln cch qung gia 2 ln t hng? Bi gii 11 1/ Lng t hng kinht tnh theo m hnh POQ

Q*=

pdH

SD

1

2 =

3216140

000.8000.202 xx = 4.000 n v

Trong : d=96/6 = 16 P =8.000/250 =32 H= 4% x1.000 = 40 S=20.000 2/ im t hng li : Lx d = 8x16 = 128 n v 3/ Tng chi ph v hng tn kho hng nm. TC= Ch+ Ctt Ch= (8.000/4000) x 20.000 = 40.000

Ctt= HpdQ

1

2= 40

32161

24000

= 40.000

TC= 40.000 +40.000 = 80.000 4/ s ln t hng ti u trong nm 8000/4000= 2 ln 5/ S ngy cch qung gia 2 ln cung ng : 250 ngy/2 =125 ngy Bi 12: Cng ty TNHH Bnh Minh cn mua vn p ca Cng ty VINAPLYCO ng thng hng xut khu.VINAPLYCO cho hng vi gi c chit khu nh sau i vi vn p (4x8x6) lai A. Bit rng chi ph t hng mi ln l 450.000 ng. Chi ph tn tr bng 20% GI MUA. Nhu cu hng nm ca Cng ty Bnh Minh l 100 tm

S lng t hng Gi mi tm 0 ->9 tm 180.000

10 -> 50 tm 175.000 >50 tm 172.000

Vy mi ln t hng l bao nhiu cho c li ?

Bi gii 12: Ta tnh cc mc sn lng Q* vi cc mc gi cho.

Q*1= 000.1802.0000.4501002

xxx = 50

Q*2= 000.1752.0

000.4501002xxx = 50,7

Q*3= 000.1722.0

000.4501002xxx = 51

Sn lng Q* =50 s mua vi gi 175.000 ng ch khng mua vi gi 180.000 do Q* =50 l v ngha. Chng ta ch cn so snh Q2*= 50 v Q3* = 51. Mun so snh ta tnh tng chi ph ca hng tn kho 2 mc sn lng trn.

TC50 = 100 x 175.000 + 000.270.19000.1742.02

50000.45050

100 =+ xxx

TC51 = 100 x 172.000 + xxx 545.959.18000.1722.0251000.450

51100 =+

Vy sn lng ti u l Q*= 51 v c TC min = 18.959.545.