Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 11,
there are 7 less packets and 5 stickers extra.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 11 |
Number |
1 u |
1 u - 7 |
Value |
9 |
11 |
Total value |
9 u |
11 u - 72 |
(a)
Let the number of packets of 9 be 1 u.
Number of stickers if they are in packets of 9
= 1 u x 9
= 9 u
Number of stickers if they are in packets of 11
= 11(1 u - 7) + 5
= 11 u - 77 + 5
= 11 u - 72
9 u = 11 u - 72
11 u - 9 u = 72
2 u = 72
1 u = 72 ÷ 2 = 36
Number of packets of 9
= 1 u
= 36
(b)
Number of stickers
= 9 u
= 9 x 36
= 324
Answer(s): (a) 36; (b) 324