1 marble costs $5.
For every 10 marbles bought, a discount of $4 is given.
- How much do 10 marbles cost?
- How much do 17 marbles cost?
- How much do 37 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 5 - 4
= 50 - 4
= $46
(b)
Number of marbles that do not belong to a set
= 17 ÷ 10
= 1 r 7
Cost of the 7 extra marbles
= 7 x 5
= $35
Cost of 17 marbles
= 46 + 35
= $81
(c)
Number of sets of 10 marbles
= 37 ÷ 10
= 3 r 7
Cost of 30 marbles
= 3 x 46
= $138
Cost of 7 marbles
= 7 x 5
= $35
Cost of 37 marbles
= 138 + 35
= $173
Answer(s): (a) $46; (b) $81; (c) $173