1 sticker costs $4.
For every 10 stickers bought, a discount of $4 is given.
- How much do 10 stickers cost?
- How much do 15 stickers cost?
- How much do 31 stickers cost?
(a)
Cost of every 10 stickers
= 10 x 4 - 4
= 40 - 4
= $36
(b)
Number of stickers that do not belong to a set
= 15 ÷ 10
= 1 r 5
Cost of the 5 extra stickers
= 5 x 4
= $20
Cost of 15 stickers
= 36 + 20
= $56
(c)
Number of sets of 10 stickers
= 31 ÷ 10
= 3 r 1
Cost of 30 stickers
= 3 x 36
= $108
Cost of 1 stickers
= 1 x 4
= $4
Cost of 31 stickers
= 108 + 4
= $112
Answer(s): (a) $36; (b) $56; (c) $112