Oscar had some chocolate chip puffs and vanilla puffs. He gave away 160 puffs to his brother. 20% of them were chocolate chip puffs and the rest were vanilla puffs.

1. How many vanilla puffs did he give his brother?
2. Oscar gave some chocolate chip puffs to his sister. ³₅ of all the puffs he gave away to his brother and his sister were chocolate chip puffs. How many chocolate chip puffs did he give his sister?

(a)
Percentage of vanilla puffs
= 100% - 20%
= 80%

Number of vanilla puffs that Oscar gave to his brother
= 80% x 160
= ⁸⁰₁₀₀ x 160
= 128 

(b)
Fraction of all the puffs he gave away to his brother and his sister that were vanilla puffs
= 1 - ³₅
= ²₅

2 u = 128

1 u = 128 ÷ 2 = 64

Number of chocolate chip puffs that Oscar gave to his brother and his sister
= 3 u
= 3 x 64
= 192

Number of chocolate chip puffs that Oscar gave to his brother
= 160 - 128
= 32

Number of chocolate chip puffs that Oscar gave to his sister
= 192 - 32
= 160

Answer(s): (a) 128; (b) 160