Some stickers are packed into exactly packets of 13.
If the stickers are repacked into packets of 9,
there are 7 more packets and 5 stickers left.
- How many packets are there?
- How many stickers are there?
|
Packets of 13 |
Packets of 9 |
Number |
1 u |
1 u + 7 |
Value |
13 |
9 |
Total value |
13 u |
9(1 u + 7) + 5 = 9 u + 68 |
(a)
Let the number of packets of 13 be 1 u.
Number of stickers if they are in packets of 13
= 1 u x 13
= 13 u
Number of stickers if they are in packets of 9
= 9 x (1 u + 7) + 5
= 9 u + 63 + 5
= 9 u + 68
13 u = 9 u + 68
13 u - 9 u = 68
4 u = 68
1 u = 68 ÷ 4 = 17
Number of packets of 13
= 1 u
= 17
(b)
Number of stickers
= 13 u
= 13 x 17
= 221
Answer(s): (a) 17; (b) 221