The elements 'A' and 'B' combine together to give two compounds A₂B₃ and AB₂. The weight of 0.2 mole of A₂B₃ is 26gm. The weight of 0.3 mole of AB₂ is 24gm. Then the atomic weights of A and B respectively

Weight of 0.2 moles of A₂B₃ = 26grams

Weight of one mole of A₂B₃ = 130grams

GMW of A₂B₃ = 130g

2A + 3B = 130.....(1)

Weight of 0.3 moles of AB₂ = 24g

Weight of 1 moles of AB₂ = 80g

GMW of AB₂ = 80g

A + 2B = 80.....(2)

Eq(1) 2A + 3B = 130

Eq(2) $\times$2,

 2A + 4B = 160.....(3)

Eq(3) - Eq(1)

B = 30

Substituting the value of 'B' in Eq(1)

2A + 3(30) = 130

A = 20