Time and Work Practice Test 2 with solutions

Question : 35 of 40

Marks: +1, -0

A is thrice as good a workman as B and therefore is able to finish a job in 60 days less than B, working together, they can do it in:

30 days
25 days
$22 1/2$ days
20 days

Validate

Solution:

Ratio of efficiency of A and B = 3 : 1
Hence, ratio of their time taking = 1 : 3
Let A and B can finish the job in x and 3x days respectively.
Now, 3x – x = 60
⇒ 2x = 60
∴ x = 30 days
& also, 3x = 3 × 30 = 90 days
(A + B)'s 1 day's work =

1/{30}+1/{90}

4/{90}

2/{45}

Hence, working together they will finish the job in

{45}/2

22 1/2

days.

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