At a book shop, pencils are sold at $9 for 1 pencil. For every 7 pencils a customer pays, an extra pencil will be given free.
- How much will Mrs Oh pay for 15 pencils?
- What is the most number of pencils Mr Tang can get for $128?
(a)
Number of pencils in one set
= 7 + 1
= 8
Cost of a set of 8 pencils
= 7 x 9
= $63
Number of sets
= 15 ÷ 8
= 1 r 7
Amount that Mrs Oh paid
= 1 x 63 + 7 x 9
= 63 + 63
= $126
(b)
Maximum number of sets
= 128 ÷ 63
= 2 r 15
Number of pencils that can be bought with remaining money
= 15 ÷ 9
= 2
Maximum number of pencils
= 8 x 2 + 2
= 18
Answer(s): (a) $126; (b) 18