1 marble costs $8.
For every 10 marbles bought, a discount of $5 is given.
- How much do 10 marbles cost?
- How much do 16 marbles cost?
- How much do 24 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 8 - 5
= 80 - 5
= $75
(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
= 75 + 48
= $123
(c)
Number of sets of 10 marbles
= 24 ÷ 10
= 2 r 4
Cost of 20 marbles
= 2 x 75
= $150
Cost of 4 marbles
= 4 x 8
= $32
Cost of 24 marbles
= 150 + 32
= $182
Answer(s): (a) $75; (b) $123; (c) $182