Question Detail
A alone can complete a work in 16 days and B alone can do in 12 days. Starting with A, they work on alternate days. The total work will be completed in
- \begin{aligned} 13\frac{1}{4} \end{aligned}
- \begin{aligned} 13\frac{1}{2} \end{aligned}
- \begin{aligned} 13\frac{3}{4} \end{aligned}
- \begin{aligned} 13\frac{4}{4} \end{aligned}
Answer: Option C
Explanation:
A's 1 day work = 1/16
B's 1 day work = 1/12
As they are working on alternate day's
So their 2 days work = (1/16)+(1/12)
= 7/48
[here is a small technique, Total work done will be 1, right, then multiply numerator till denominator, as 7*6 = 42, 7*7 = 49, as 7*7 is more than 48, so we will consider 7*6, means 6 pairs ]
Work done in 6 pairs = 6*(7/48) = 7/8
Remaining work = 1-7/8 = 1/8
On 13th day it will A turn,
then remaining work = (1/8)-(1/16) = 1/16
On 14th day it is B turn,
1/12 work done by B in 1 day
1/16 work will be done in (12*1/16) = 3/4 day
So total days =
\begin{aligned} 13\frac{3}{4} \end{aligned}
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