1 marble costs $8.
For every 10 marbles bought, a discount of $6 is given.
- How much do 10 marbles cost?
- How much do 15 marbles cost?
- How much do 27 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
= 15 ÷ 10
= 1 r 5
Cost of the 5 extra marbles
= 5 x 8
= $40
Cost of 15 marbles
= 74 + 40
= $114
(c)
Number of sets of 10 marbles
= 27 ÷ 10
= 2 r 7
Cost of 20 marbles
= 2 x 74
= $148
Cost of 7 marbles
= 7 x 8
= $56
Cost of 27 marbles
= 148 + 56
= $204
Answer(s): (a) $74; (b) $114; (c) $204