Change each mixed fraction to improper
3 2/5 = 15/5 + 2/5 = 17/5
9 1/10 = 90/10 + 1/10 = 91/10
Find a common denominator. Multiply 2 to both numerator and denominator of 17/5
17/5(2/2) = 34/10
34/10 + 91/10 = 125/10
125/10
Simplify. Divide
125/10 = 12.5
12.5 is your answer
hope this helps