Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 18,
there are 7 less packets.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 18 |
Number |
1 u |
1 u - 7 |
Value |
9 |
18 |
Total value |
9 u |
18(1 u - 7) = 18 u - 126 |
(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 - 7)
= 18 u - 126
9 u = 18 u - 126
18 u - 9 u = 126
9 u = 126
1 u = 126 ÷ 9 = 14
Number of packets of 9 = 14
(b)
Number of stickers
= 9 u
= 9 x 14
= 126
Answer(s): (a) 14; (b) 126