# Time & Work SBI PO Quiz

1. A and B together can do a piece of work in 12 days, while B alone can finish it in 30 days. A alone can
finish the work in
1) 15days  2) 18 days  3) 20 days  4) 25 days   5) None of these
Solution: (3).
(A+B)’ s 1 day’s work = 1/12
B’s 1 day’s work = 1/30
Therefore A’s 1 days’s work = 1/12 – 1/30
= 5-2 / 60 = 1/20

2. A and B can do a piece of work in 72 days. B and C can do it in 120 days. A and C can do it in 90 days.
In what time can A alone do it?
1) 80 days  2) 100 days  3) 120 days  4) 150 days  5) None of these
Solution: (3).
( A+B)’s 1 days’s work = 1/72
( B+C)’s 1 day’s work = 1/120
(A+C)’s 1 day’s work = 1/90
2((A+B+C)’s 1 day’s work
= 1/72 + 1/120 + 1/90
Therefore ( A+B+C)’s 1 day’s work
= (5+3+4) / (360 x 2) = (12/360 x 2 ) = 1/60
Therefore A’s 1 days’s work = (A+B+C)’s 1 day’s work – ( B+C)’s 1 day’s work
= 1/60 – 1/120 = 2 – 1 /120 = 1/120
Therefore A alone can finish the work in 120 days.

3. ’A’can do a piece of work in x days and B can do the same work 3x days. To finish the work together
they take 12 days. What is the value of x?
1) 8  2) 10  3) 12  4) 16  5) None of these

Solution: (4).
A’s 1 day’s work A = 1/x
B’s 1 day’s work B = 1/3x
( A+B)’s 1 day’s work
= 1/x + 1/3x = 4/3x
And given one day work of both A and B = 1/12
= 4/3x = 1/12 = 3x = 48 = x = 16

4. A can do a piece of work in 10 days and B in 20 days . They begin together but A leaves 2 days before
the completion of the work. The whole work will be done in
1) 8 days  2) 7 2/3  3) 7 days  4) 6 days  5) None of these
Solution: (1).
Here, a = 10 , b = 20 and x = 2
Therefore required time = ( a + x) *b / (a + b)
= (10 + 2) *20 / 30 = 8 days

5. A and B can complete a job in 24 days working together. A alone can complete it in 32 days. Both of
them worked together for 8 days and then A left. The number of days B will take to complete the
remaining job is
1)16 2)32 3)64 4)128 5)None of these
Solution: (3).
Let B will take x days to complete the remaining job .
According to the question,
1/A + 1/B = 1/24 and 1/A = 1/32
Therefore 1/B = 1/24 – 1/32 = 1/96 = B = 96 days
According to the question,
8 ( 1/A + 1/B ) + x * 1/B = 1

= 8 x 1/24 + x/96 = 1
= 1/3 + x/96 = 1
x/96 = 1 – 1/3
therefore x = 2*96 /3 = 64
Hence, B complete the remaining job in 64 days.

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