felixjkz wrote:
This explanation is vague since you picked 1/2. We cannot see how it works because it does not matter what you do with x and y it's around 1/2.
I see that formula is absolutely correct but don't understand why if the value of 1/x is 2/6 and 1/y is 3/6, the portion which y should not do comes out as 3/5 not 2/5.
The explanation was meant for saswani who had trouble understanding "Then why do we multiply the rate of only A with the total time?"
It doesn't matter what the numbers are - as long as they are easy to work with - you can make out what's going on.
As for your question "why if the value of 1/x is 2/6 and 1/y is 3/6, the portion which y should not do comes out as 3/5 not 2/5."
If x = 3 and y = 2,
A does 1/3rd work in 1 hr and B does 1/2 work in 1 hr.
When they work together, they complete the work in 1/(1/2 + 1/3) = 6/5 hrs
In 6/5 hrs, A does (1/3)*(6/5) = 2/5 work
and B does (1/2)*(6/5) = 3/5 work
So B does NOT need to do 2/5 of the work. Answer still (E).
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