jlgdr wrote:

jusjmkol740 wrote:

If Dev works alone he will take 20 more hours to complete a task than if he worked with Tina to complete the task. If Tina works alone, she will take 5 more hours to complete the complete the task, then if she worked with Dev to complete the task? What is the ratio of the time taken by Dev to that taken by Tina if each of them worked alone to complete the task?

A. 4 : 1

B. 2 : 1

C. 10 : 1

D. 3 : 1

E. 1 : 2

Is there any way to solve this problem in a time efficient way?

Experts please advice

Cheers

J

Let's say when they work together, they take t hrs to complete the work.

Dev takes 20 hrs extra when working alone because Tina did not work for t hrs and that work Dev had to do. Ratio of time take by Dev/Tina to do the same work = 20/t

Tina takes 5 hrs extra when working alone because Dev did not work with her for t hrs and hence his part of work, Tine did in 5 hrs. Ratio of time taken by Dev/Tina to do the same work = t/5

20/t = t/5 (The ratio of time taken by Dev and Tina

for the same work will always be the same irrespective of the amount of work)

t = 10

Ratio of time taken by Dev/Tina = 20:10 = 2:1

Answer (B)

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