Some stickers are packed into exactly packets of 5.
If the stickers are repacked into packets of 15,
there are 2 less packets.
- How many packets are there?
- How many stickers are there?
|
Packets of 5 |
Packets of 15 |
Number |
1 u |
1 u - 2 |
Value |
5 |
15 |
Total value |
5 u |
15(1 u - 2) = 15 u - 30 |
(a)
Let the number of packets of 5 be 1 u.
Number of stickers in packets of 5
= 1 u x 5
= 5 u
Number of stickers in packets of 15
= 15 x (1 u - 2)
= 15 u - 30
5 u = 15 u - 30
15 u - 5 u = 30
10 u = 30
1 u = 30 ÷ 10 = 3
Number of packets of 5 = 3
(b)
Number of stickers
= 5 u
= 5 x 3
= 15
Answer(s): (a) 3; (b) 15