1 sticker costs $7.
For every 10 stickers bought, a discount of $7 is given.
- How much do 10 stickers cost?
- How much do 12 stickers cost?
- How much do 21 stickers cost?
(a)
Cost of every 10 stickers
= 10 x 7 - 7
= 70 - 7
= $63
(b)
Number of stickers that do not belong to a set
= 12 ÷ 10
= 1 r 2
Cost of the 2 extra stickers
= 2 x 7
= $14
Cost of 12 stickers
= 63 + 14
= $77
(c)
Number of sets of 10 stickers
= 21 ÷ 10
= 2 r 1
Cost of 20 stickers
= 2 x 63
= $126
Cost of 1 stickers
= 1 x 7
= $7
Cost of 21 stickers
= 126 + 7
= $133
Answer(s): (a) $63; (b) $77; (c) $133