Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 18,
there are 5 less packets.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 18 |
Number |
1 u |
1 u - 5 |
Value |
9 |
18 |
Total value |
9 u |
18(1 u - 5) = 18 u - 90 |
(a)
Let the number of packets of 9 be 1 u.
Number of stickers in packets of 9
= 1 u x 9
= 9 u
Number of stickers in packets of 18
= 18 x (1 u - 5)
= 18 u - 90
9 u = 18 u - 90
18 u - 9 u = 90
9 u = 90
1 u = 90 ÷ 9 = 10
Number of packets of 9 = 10
(b)
Number of stickers
= 9 u
= 9 x 10
= 90
Answer(s): (a) 10; (b) 90