Adam pays $2.40 for a marble and a sticker.
The marble costs 7 times as much as the sticker.
- What is the cost of 1 marble?
- How much is the cost of 3 stickers and 5 marbles?
(a)
Cost of a sticker = 1 u
Cost of a marble = 7 u
Total cost of a sticker and a marble
= 1 u + 7 u
= 8 u
8 u = 2.40
1 u = 2.40 ÷ 8 = 0.30
Cost of the marble
= 7 u
= 7 x 0.30
= $2.10
(b)
Cost of 3 stickers and 5 marbles
= 3 x 1 u + 5 x 7 u
= 3 u + 35 u
= 38 u
= 38 x 0.30
= $11.40
Answer(s): (a) $2.10; (b) $11.40