1 marble costs $5.
For every 10 marbles bought, a discount of $4 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 38 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
= 14 ÷ 10
= 1 r 4
Cost of the 4 extra marbles
= 4 x 5
= $20
Cost of 14 marbles
= 46 + 20
= $66
(c)
Number of sets of 10 marbles
= 38 ÷ 10
= 3 r 8
Cost of 30 marbles
= 3 x 46
= $138
Cost of 8 marbles
= 8 x 5
= $40
Cost of 38 marbles
= 138 + 40
= $178
Answer(s): (a) $46; (b) $66; (c) $178