1 marble costs $4.
For every 10 marbles bought, a discount of $7 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 37 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 4 - 7
= 40 - 7
= $33
(b)
Number of marbles that do not belong to a set
= 14 ÷ 10
= 1 r 4
Cost of the 4 extra marbles
= 4 x 4
= $16
Cost of 14 marbles
= 33 + 16
= $49
(c)
Number of sets of 10 marbles
= 37 ÷ 10
= 3 r 7
Cost of 30 marbles
= 3 x 33
= $99
Cost of 7 marbles
= 7 x 4
= $28
Cost of 37 marbles
= 99 + 28
= $127
Answer(s): (a) $33; (b) $49; (c) $127