1 marble costs $8.
For every 10 marbles bought, a discount of $6 is given.
- How much do 10 marbles cost?
- How much do 19 marbles cost?
- How much do 35 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 8 - 6
= 80 - 6
= $74
(b)
Number of marbles that do not belong to a set
= 19 ÷ 10
= 1 r 9
Cost of the 9 extra marbles
= 9 x 8
= $72
Cost of 19 marbles
= 74 + 72
= $146
(c)
Number of sets of 10 marbles
= 35 ÷ 10
= 3 r 5
Cost of 30 marbles
= 3 x 74
= $222
Cost of 5 marbles
= 5 x 8
= $40
Cost of 35 marbles
= 222 + 40
= $262
Answer(s): (a) $74; (b) $146; (c) $262