Question

the efficiency of x and y is in the ratio 3:5 .if x can do piece of work in 20 hours then y can do it in how many hours​

Answer 1

Here is the answer: (ignore the blue text on first line)

Answer 2

Answer:

Y can do the piece of work in 12 hours.

Given:

The efficiency of X and Y is in the ratio 3:5. X can do piece of work in 20 hours  

To find:  

Y can do it in how many hours

Solution:  

Let the ratio of x and y be 3a : 5a

By property of inverse proportion,  

$\frac{5 a}{3 a}=\frac{20}{y}$

y = $\frac{20 \times 3}{5}$

y = 12

Result:

Y can do the piece of work in 12 hours.