120
for [tex]\frac{8}{15}[/tex] to be equal to [tex]\frac{15}{?}[/tex]
consider the numerators 8 × 8 = 64, the numerator of the second fraction
We must therefore multiply the denominator by 8
15 × 8 = 120
thus [tex]\frac{8}{15}[/tex] = [tex]\frac{64}{120}[/tex]