1 bead costs $3.
For every 10 beads bought, a discount of $3 is given.
- How much do 10 beads cost?
- How much do 13 beads cost?
- How much do 21 beads cost?
(a)
Cost of every 10 beads
= 10 x 3 - 3
= 30 - 3
= $27
(b)
Number of beads that do not belong to a set
= 13 ÷ 10
= 1 r 3
Cost of the 3 extra beads
= 3 x 3
= $9
Cost of 13 beads
= 27 + 9
= $36
(c)
Number of sets of 10 beads
= 21 ÷ 10
= 2 r 1
Cost of 20 beads
= 2 x 27
= $54
Cost of 1 beads
= 1 x 3
= $3
Cost of 21 beads
= 54 + 3
= $57
Answer(s): (a) $27; (b) $36; (c) $57