Question

two numbers are respectively 20%and 50%of a third number. what percentage is the first number of the second?

Answer 1

let third number be x
first number = 20% of x =20x /100
second number = 50% of =50x / 100
percentage of first no of second no
= {(20x /100) / (50x / 100)}×100
=(2×100) / 20
=40%

Answer 2

The percentage three no. be x
$first \: no. = \frac{20}{100} \times \: x$
$= \frac{20 x}{100}$
$second \: no. = \frac{50}{100} \times x$
$= \frac{50x}{100}$
x=(20x/100×50x/100)×100
=2/5×100
x=40%