Adam spends $14.60 on 3 marbles and 4 stickers.
A marble costs $2.30 more than 1 sticker.
- How much does 1 marble cost?
- How much do 8 marbles cost?
- How much do a sticker and 8 marbles cost?
- How much do 8 marbles cost more than 1 sticker?
(a)
Let the cheaper item be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.30
Total cost of 3 marbles and 4 stickers
= 3(1 u + 2.30) + 4 u
= 3 u + 6.90 + 4 u
= 3 u + 4 u + 6.90
= 7 u + 6.90
7 u + 6.90 = 14.60
7 u = 14.60 - 6.90
7 u = 7.70
1 u = 7.70 ÷ 7 = 1.10
Cost of 1 marble
= 1 u + 2.30
= 1.10 + 2.30
= $3.40
(b)
Cost of 8 marbles
= 8 x 3.40
= $27.20
(c)
Cost of 1 sticker and 8 marbles
= 1.10 + 27.20
= $28.30
(d)
Cost of 8 marbles more than 1 sticker
= 27.20 - 1.10
= $26.10
Answer(s): (a) $3.40; (b) $27.20; (c) $28.30; (d) $26.10