1 marble costs $5.
For every 10 marbles bought, a discount of $3 is given.
- How much do 10 marbles cost?
- How much do 14 marbles cost?
- How much do 36 marbles cost?
(a)
Cost of every 10 marbles
= 10 x 5 - 3
= 50 - 3
= $47
(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
= 47 + 20
= $67
(c)
Number of sets of 10 marbles
= 36 ÷ 10
= 3 r 6
Cost of 30 marbles
= 3 x 47
= $141
Cost of 6 marbles
= 6 x 5
= $30
Cost of 36 marbles
= 141 + 30
= $171
Answer(s): (a) $47; (b) $67; (c) $171