Some stickers are packed into exactly packets of 15.
If the stickers are repacked into packets of 9,
there are 7 more packets and 3 stickers left.
- How many packets are there?
- How many stickers are there?
|
Packets of 15 |
Packets of 9 |
Number |
1 u |
1 u + 7 |
Value |
15 |
9 |
Total value |
15 u |
9(1 u + 7) + 3 = 9 u + 66 |
(a)
Let the number of packets of 15 be 1 u.
Number of stickers if they are in packets of 15
= 1 u x 15
= 15 u
Number of stickers if they are in packets of 9
= 9 x (1 u + 7) + 3
= 9 u + 63 + 3
= 9 u + 66
15 u = 9 u + 66
15 u - 9 u = 66
6 u = 66
1 u = 66 ÷ 6 = 11
Number of packets of 15
= 1 u
= 11
(b)
Number of stickers
= 15 u
= 15 x 11
= 165
Answer(s): (a) 11; (b) 165