1 marble costs $6.
For every 10 marbles bought, a discount of $6 is given.
- How much do 10 marbles cost?
- How much do 16 marbles cost?
- How much do 33 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 6 - 6
= 60 - 6
= $54
(b)
Number of marbles that do not belong to a set
= 16 ÷ 10
= 1 r 6
Cost of the 6 extra marbles
= 6 x 6
= $36
Cost of 16 marbles
= 54 + 36
= $90
(c)
Number of sets of 10 marbles
= 33 ÷ 10
= 3 r 3
Cost of 30 marbles
= 3 x 54
= $162
Cost of 3 marbles
= 3 x 6
= $18
Cost of 33 marbles
= 162 + 18
= $180
Answer(s): (a) $54; (b) $90; (c) $180