9. Multiply the money he has by the portion he spent:
75 x 3/5 = (75 x3)/5 = 225/5 = 45
He spent $45
10. First rewrite 4 1/8 as an improper fraction
33/8
Now multiply by 1/3:
33/8 x 1/3 = (33 x1) /(8 x 3) = 33/24 = 1 3/8
She spent 1 3/8 hours studying math.