1 marble costs $8.
For every 10 marbles bought, a discount of $3 is given.
- How much do 10 marbles cost?
- How much do 16 marbles cost?
- How much do 22 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 8 - 3
= 80 - 3
= $77
(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
= 77 + 48
= $125
(c)
Number of sets of 10 marbles
= 22 ÷ 10
= 2 r 2
Cost of 20 marbles
= 2 x 77
= $154
Cost of 2 marbles
= 2 x 8
= $16
Cost of 22 marbles
= 154 + 16
= $170
Answer(s): (a) $77; (b) $125; (c) $170