Question

40-y
5
-------- = ---
30 6

Answer 1

$\frac{40-y}{30}=\frac{5}{6}\\\\\frac{40-y}{30}*30=\frac{5}{6}*30\\\\40-y=5*5\\\\-y=25-40\\\\-y=-15\\\\y=15\\\\Otvet:\boxed{15}$