Ответ:

a) Barno Hanifadan 3 marta katta, demak Barnoning yoshi \(3x\). Sevinch undan 4 yosh kichik: \(3x-4\).

b) Hanifa 10 yoshda bo‘lsa, Sevinchning yoshi \(3\cdot10-4=26\). Farqi: \(26-10=16\).

Javob: a) \(3x-4\) yosh; b) Sevinch Hanifadan 16 yosh katta.