1 marble costs $6.
For every 10 marbles bought, a discount of $5 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 24 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 6 - 5
= 60 - 5
= $55
(b)
Number of marbles that do not belong to a set
= 14 ÷ 10
= 1 r 4
Cost of the 4 extra marbles
= 4 x 6
= $24
Cost of 14 marbles
= 55 + 24
= $79
(c)
Number of sets of 10 marbles
= 24 ÷ 10
= 2 r 4
Cost of 20 marbles
= 2 x 55
= $110
Cost of 4 marbles
= 4 x 6
= $24
Cost of 24 marbles
= 110 + 24
= $134
Answer(s): (a) $55; (b) $79; (c) $134