prep 3

[Chaitanya_1986]

Please Help

[Anurag@Gurome]

Please Help

This would be much easier if we use the picking numbers approach in this question.
Let c = 8 and h = 10 (while picking numbers, do remember that c < h).
1 hr work of cold water leak = 1/8 and 1 hr work of hot water leak = 1/10
Now 1/t = 1/8 + 1/10 = 18/80 = 9/40 or t = 40/9
Next, check the given options to see which are true.

(1) 0 < 40/9 < 10, holds true.
(2) 8 < 40/9 < 10, not true.
(3) 8/2 < 40/9 < 10/2 or 4 < 40/9 < 5, holds true.

Since, (1) and (3) hold true, the correct answer is E.

[kannans3]

As Anurag mentioned this problem can best be approached by picking numbers.

Let c = 2hrs
h = 4hrs

In 1hr c can fill 1/2 bucket
In 1 hr h can fill 1/4 bucket

Note - Less time means more job completed.

Therefore, 1/2 + 1/4 = 1/t

3/4 = 1/t
t = 4/3

Now substitute the target value & picked value in the statements.
Statement 1: 0 < 4/3 < 4 => Turns out to be true
So, answer can be A, D or E.
Statement 2: 2 < 4/3 < 4 Turns out to be false as 4/3 is less than 2.
So, answer can be A or E.
Statement 3: 2/2 < 4/3 < 4/2 => Turns out to be true

So answer = E.