1 bead costs $9.
For every 10 beads bought, a discount of $6 is given.
- How much do 10 beads cost?
- How much do 18 beads cost?
- How much do 21 beads cost?
(a)
Cost of every 10 beads
= 10 x 9 - 6
= 90 - 6
= $84
(b)
Number of beads that do not belong to a set
= 18 ÷ 10
= 1 r 8
Cost of the 8 extra beads
= 8 x 9
= $72
Cost of 18 beads
= 84 + 72
= $156
(c)
Number of sets of 10 beads
= 21 ÷ 10
= 2 r 1
Cost of 20 beads
= 2 x 84
= $168
Cost of 1 beads
= 1 x 9
= $9
Cost of 21 beads
= 168 + 9
= $177
Answer(s): (a) $84; (b) $156; (c) $177