# If 20% of A = 50% of B, Then what per cent of A is B ?

If 20% of A = 50% of B, Then what per cent of A is B ?
[A]15%
[B]25%
[C]30%
[D]40%

40%
20% of A = 50% of B
$=> 2A = 5B$
$=> A = \frac{5B}{2}$
Let B is x% of A.
$\therefore \frac{5B}{2}\times \frac{x}{100} = B$
$=> x = \frac{200}{5} = 40\%$
Hence option [D] is the correct answer.