Help me please. Cant get my head around this one

Question

In the reaction below, how many moles of A₂ will be used to produced 2.45 mol of XA?

a. Balance the chemical equation:   XY₃ +   A₂ →   XA +  Y₂A

b.    moles A₂

Answer 1

XY₃ +   A₂ →   XA +  Y₂A ... unbalanced

4XY₃ +   5A₂ →   4XA +  6Y₂A ... balanced equation

b) 2.45 mol XA x 5 mol A₂ / 4 mol XA = 3.06 mol A₂