1 marble costs $8.
For every 10 marbles bought, a discount of $3 is given.
- How much do 10 marbles cost?
- How much do 19 marbles cost?
- How much do 34 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
= 19 ÷ 10
= 1 r 9
Cost of the 9 extra marbles
= 9 x 8
= $72
Cost of 19 marbles
= 77 + 72
= $149
(c)
Number of sets of 10 marbles
= 34 ÷ 10
= 3 r 4
Cost of 30 marbles
= 3 x 77
= $231
Cost of 4 marbles
= 4 x 8
= $32
Cost of 34 marbles
= 231 + 32
= $263
Answer(s): (a) $77; (b) $149; (c) $263