Mark had some strawberry cupcakes and vanilla cupcakes. He gave away 60 cupcakes to his sister. 10% of them were strawberry cupcakes and the rest were vanilla cupcakes.

1. How many vanilla cupcakes did he give his sister?
2. Mark gave some strawberry cupcakes to his cousin. ⁴₇ of all the cupcakes he gave away to his sister and his cousin were strawberry cupcakes. How many strawberry cupcakes did he give his cousin?

(a)
Percentage of vanilla cupcakes
= 100% - 10%
= 90%

Number of vanilla cupcakes that Mark gave to his sister
= 90% x 60
= ⁹⁰₁₀₀ x 60
= 54 

(b)
Fraction of all the cupcakes he gave away to his sister and his cousin that were vanilla cupcakes
= 1 - ⁴₇
= ³₇

3 u = 54

1 u = 54 ÷ 3 = 18

Number of strawberry cupcakes that Mark gave to his sister and his cousin
= 4 u
= 4 x 18
= 72

Number of strawberry cupcakes that Mark gave to his sister
= 60 - 54
= 6

Number of strawberry cupcakes that Mark gave to his cousin
= 72 - 6
= 66

Answer(s): (a) 54; (b) 66