Let atomic weight of A=x and atomic weight of B=y ∴ Molar mass of A2B=2x+y and molar mass of AB3=x+3y Now, weight of 0.15 moles of A2B=(2x+y)0.15 and weight of 0.15 moles of AB3=(x+3y)0.15 Given, weight of 0.15 moles of A2B and AB3 are equal. ∴(2x+y)0.15=(x+3y)0.15 ⇒x=2y ⇒‌
x
y
=2 ∴ Atomic weight of A is 2 times of atomic weight of B.