1 marble costs $8.
For every 10 marbles bought, a discount of $4 is given.
- How much do 10 marbles cost?
- How much do 16 marbles cost?
- How much do 28 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 8 - 4
= 80 - 4
= $76
(b)
Number of marbles that do not belong to a set
= 16 ÷ 10
= 1 r 6
Cost of the 6 extra marbles
= 6 x 8
= $48
Cost of 16 marbles
= 76 + 48
= $124
(c)
Number of sets of 10 marbles
= 28 ÷ 10
= 2 r 8
Cost of 20 marbles
= 2 x 76
= $152
Cost of 8 marbles
= 8 x 8
= $64
Cost of 28 marbles
= 152 + 64
= $216
Answer(s): (a) $76; (b) $124; (c) $216