1 marble costs $6.
For every 10 marbles bought, a discount of $4 is given.
- How much do 10 marbles cost?
- How much do 12 marbles cost?
- How much do 33 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 6 - 4
= 60 - 4
= $56
(b)
Number of marbles that do not belong to a set
= 12 ÷ 10
= 1 r 2
Cost of the 2 extra marbles
= 2 x 6
= $12
Cost of 12 marbles
= 56 + 12
= $68
(c)
Number of sets of 10 marbles
= 33 ÷ 10
= 3 r 3
Cost of 30 marbles
= 3 x 56
= $168
Cost of 3 marbles
= 3 x 6
= $18
Cost of 33 marbles
= 168 + 18
= $186
Answer(s): (a) $56; (b) $68; (c) $186