Carl had some banana doughnuts and cheese doughnuts. He gave away 175 doughnuts to his brother. 20% of them were banana doughnuts and the rest were cheese doughnuts.

1. How many cheese doughnuts did he give his brother?
2. Carl gave some banana doughnuts to his sister. ³₇ of all the doughnuts he gave away to his brother and his sister were banana doughnuts. How many banana doughnuts did he give his sister?

(a)
Percentage of cheese doughnuts
= 100% - 20%
= 80%

Number of cheese doughnuts that Carl gave to his brother
= 80% x 175
= ⁸⁰₁₀₀ x 175
= 140 

(b)
Fraction of all the doughnuts he gave away to his brother and his sister that were cheese doughnuts
= 1 - ³₇
= ⁴₇

4 u = 140

1 u = 140 ÷ 4 = 35

Number of banana doughnuts that Carl gave to his brother and his sister
= 3 u
= 3 x 35
= 105

Number of banana doughnuts that Carl gave to his brother
= 175 - 140
= 35

Number of banana doughnuts that Carl gave to his sister
= 105 - 35
= 70

Answer(s): (a) 140; (b) 70