1 marble costs $8.
For every 10 marbles bought, a discount of $3 is given.
- How much do 10 marbles cost?
- How much do 17 marbles cost?
- How much do 35 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
= 17 ÷ 10
= 1 r 7
Cost of the 7 extra marbles
= 7 x 8
= $56
Cost of 17 marbles
= 77 + 56
= $133
(c)
Number of sets of 10 marbles
= 35 ÷ 10
= 3 r 5
Cost of 30 marbles
= 3 x 77
= $231
Cost of 5 marbles
= 5 x 8
= $40
Cost of 35 marbles
= 231 + 40
= $271
Answer(s): (a) $77; (b) $133; (c) $271