1 marble costs $7.
For every 10 marbles bought, a discount of $6 is given.
- How much do 10 marbles cost?
- How much do 15 marbles cost?
- How much do 37 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 7 - 6
= 70 - 6
= $64
(b)
Number of marbles that do not belong to a set
= 15 ÷ 10
= 1 r 5
Cost of the 5 extra marbles
= 5 x 7
= $35
Cost of 15 marbles
= 64 + 35
= $99
(c)
Number of sets of 10 marbles
= 37 ÷ 10
= 3 r 7
Cost of 30 marbles
= 3 x 64
= $192
Cost of 7 marbles
= 7 x 7
= $49
Cost of 37 marbles
= 192 + 49
= $241
Answer(s): (a) $64; (b) $99; (c) $241