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Hi,

I tried solving the latest free quiz in the website. For the following question, I calculated the solution as 12 days while the answer given is 4 days. can you explain how it is calculated?

David completes 60% of an assigned task in 8 days and realizes that he will be behind schedule at the present rate. He takes the assistance of his younger brother Ron who is one-third as efficient as David is and completes the assigned task on schedule. How many days did David and Ron work together?

Hi

The question asked is how long did David and Ron work together?

The total work got over in 12 days. However, of the 12 days, David worked alone for 8 days and therefore, the duo worked together for only 4 days and hence the correct answer is 4 days

K S Baskar
Faculty - 4gmat

David's one day's work is 60%/8.(=A)
Rons's one Day's work is (60%*3)/8 (=B) (As Ron is one third efficient as David is. This is time and work problem, hence they are inversly proportional.)

Now we can have Their combined work per day which is A+B. i.e. 10% of the work per day. And 40 % work is left. So 4 days would be required.

Ven:

Please reproduce the question entirely. I did not find the question in the free quiz.
Shaji.

I'am sorry. No I found the question. Its from an old quiz.The solution is already in the forum .

Shaji