1 marble costs $9.
For every 10 marbles bought, a discount of $6 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 26 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 9 - 6
= 90 - 6
= $84
(b)
Number of marbles that do not belong to a set
= 14 ÷ 10
= 1 r 4
Cost of the 4 extra marbles
= 4 x 9
= $36
Cost of 14 marbles
= 84 + 36
= $120
(c)
Number of sets of 10 marbles
= 26 ÷ 10
= 2 r 6
Cost of 20 marbles
= 2 x 84
= $168
Cost of 6 marbles
= 6 x 9
= $54
Cost of 26 marbles
= 168 + 54
= $222
Answer(s): (a) $84; (b) $120; (c) $222