Chain Rule Practice Test 1 with solutions

Question : 40 of 40

Marks: +1, -0

12 men and 18 boys, working

7 1/2

hours a day, can do a piece of work in 60 days. If a man works equal to 2 boys, then how many boys will be required to help 21 men to do twice the work in 50 days, working 9 hours a day?

Validate

Solution:

Here,1 man = 2 boys
Now 12 men + 18 boys = 12 men + 9 men = 21 men

Work	Days	Hours	Men
1	60	15/2	21
2	50	9	x

⇒

x/{21}

{15}/{2×9} × {60}/{50} × 2/1

∴ x =

{15}/{2×9} × {60}/{50} × 2 × 21

= 42 men
Hence, number of additional men = 42 – 21 = 21 men
Then, 21 men = 42 boys.

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