Quantitative Aptitude: Time and Work Set 4

Time Work Problems tricks for SBI PO, IBPS PO, NIACL, NICl, LIC, Dena Bank PO PGDBF, BOI, Bank of Baroda and other competitive exams

1. A can do 2/5 work in 8 days. B can do 3/5 work in 18 days. In how many days together they can do 3/4 work?
   A) 8 days
   B) 9 days
   C) 7 days
   D) 10 days
   E) 12 days
   
   View Answer

   Option B
   Solution:
   A – 2/5 work in 8 days => total= 8*5/2= 20 days
   B- 3/5 work in 18 days => total- 30 days
   A+B together = 30*20/50 = 12 days
   hence 3/4 * 12=9 days
2. A and B can do a piece of work in 72 days. B and C can do it in 120 days. C and A can do it in 90 days. In how many days all three together can do the work?
   A) 80 days
   B) 120 days
   C) 100 days
   D) 60 days
   E) 150 days
   
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   Option D
   Solution:
   (total work=360)
   A+B= 72————-5
   B+C=120————3
   C+A=90————–4
   =>2(A+B+C)=12
   A+B+C=6
   total days=360/6=60 days
   
3. Working efficiency of A and B for completing a piece of work is in the ratio 2:3. Find the number of days they will take to complete the work together, if B takes 30 days less than A.
   A) 24 days
   B) 48 days
   C) 60 days
   D) 36 days
   E) 40 days
   
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   Option D
   Solution:
   A:B (efficiency)=2:3
   A:B(days)=3:2
   Diff=1=30
   2=60
   3=90
   A=90 days;
   B=60 days
   together A+B= 36 days
4. 6 men and 10 women can do a work in 8 days. 4 men and 12 women can do same work in 10 days. Find in how many days 3 men and 5 women can do the work.
   A) 12 days
   B) 16 days
   C) 20 days
   D) 24 days
   E) None of these
   
   View Answer

   Option B
   Solution:
   6m+10 w=8 => 48 m+ 80 w =1 —-(i)
   4 m + 12 w =10 =>40 m + 120 w=1 —-(ii)
   equate (i) and (ii)
   we get, 1 m= 5w , put this in (i)
   30 w +10 w=8 => 40 m= 8 days
   hence 3 m+ 5 w= 20 w =8*40/20=16 days
   
5. A certain number of men can complete a job in 30 days. If there were 10 men less it would be completed in 30 days more. How many men are required to complete this job in 20 days?
   A) 30 men
   B) 20 men
   C) 40 men
   D) 10 men
   E) 25 men
   
   View Answer

   Option A
   Solution:
   x*30=(x-10)*60 => x=20 men
   now 20*30=x*20 =>x=30 men
6. A and B can do a work in 30 days. They started together but after 10 days B left the work. If A did the remaining work in 40 days, then find in how many days B can alone do the work?
   A) 40 days
   B) 50 days
   C) 30 days
   D) 60 days
   E) 55 days
   
   View Answer

   Option D
   Solution:
   A+B=30
   let total work =30
   1 day work of A+B=1
   10 days – 10
   remaning work =20
   A did 20 work in 40 days
   so 30 work is done in 60 days
   A+B=30 ———– 2 (total work =60)
   A       =60 ———-1
   B= 2-1=1 => 60/1= 60 days
7. A man and a boy can complete a piece of work in 30 days. They both started the work, but in the last 6 days, only boy does the work and in this way the work got completed in 34 days. How long does the man take alone to complete the work?
   A) 30 days
   B) 45 days
   C) 60 days
   D) 90 days
   E) 85 days
   
   View Answer

   Option B
   Solution:
   1M + 1B= 30 days
   let total work= 30
   1 day work of 1 M+ 1B=1
   they work together for 34-6=28 days, so they did 28 work together
   Remaining work =30-28=2
   boy does 2 work in 6 days
   30—90 days
   M+B=30 ———3
   B=90 ————–1(total = 90)
   M= 3-1=2
   90/2=45 days
8. The average wage of 200 men is Rs 300. Later on it was discovered that the wage of two workers were misread as 50 and 30 instead of 500 and 300. The correct average was?
   A) 302.6
   B) 303.6
   C) 304.6
   D) 305.6
   E) 306.6
   
   View Answer

   Option B
   Solution:
   200*300=60000
   new correct total = 60000-50-30+500+300 = 60720
   Avg. = 60720/200 = 303.6
9. A, B and C separately can do a piece of work in 11 days, 20 days and 55 days respectively. In how many days the work will be completed if A is assisted by B and C on alternate day?
   A) 2 days
   B) 4 days
   C) 6 days
   D) 8 days
   E) 10 days
   
   View Answer

   Option D
   Solution:
   A=11 ———— 20 (total work=220)
   B=20—————11
   C=55 —————4
   A+B=31
   A+C=24
   hence 2 days work =31+24=55
   total work 220=55*4 hence total days =2*4=8 days
   
10. A can do a work in 30 days and B in 40 days. They together work for 12 days and work is completed by C in 3 days. Find in how many days C can do the same work alone?
    A) 10
    B) 12
    C) 8
    D) 15
    E) 16
    
    View Answer

    Option A
    Solution:
    A= 30 ————– 4 (Total=120)
    B=40   ————– 3
    A+B=7
    in 12 days 7*12=84 work is done. Remaining =120-84=36
    this is done by C in 3 days. Means C does 12 work in 1 day. Means 120 work in 120/12=10 days