1 marble costs $9.
For every 10 marbles bought, a discount of $5 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 33 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 9 - 5
= 90 - 5
= $85
(b)
Number of marbles that do not belong to a set
= 14 ÷ 10
= 1 r 4
Cost of the 4 extra marbles
= 4 x 9
= $36
Cost of 14 marbles
= 85 + 36
= $121
(c)
Number of sets of 10 marbles
= 33 ÷ 10
= 3 r 3
Cost of 30 marbles
= 3 x 85
= $255
Cost of 3 marbles
= 3 x 9
= $27
Cost of 33 marbles
= 255 + 27
= $282
Answer(s): (a) $85; (b) $121; (c) $282