3700 stickers are in 3 packets.
The 3rd packet has 700 stickers more than the total number of stickers in the 1st and 2nd packets.
The 2nd packet has 3 times as many stickers as the 1st packet.
How many stickers does the 3rd packet contain?
Choose the packet with the least stickers to be 1 u.

Number of stickers in the 1st packet = 1 u
Number of stickers in the 2nd packet = 3 u

Number of stickers in the 1st packet and 2nd packet
= 1 u + 3 u
= 4 u

Number of stickers in the 3rd packet = 4 u + 700

Total number of stickers
= 1 u + 3 u + 4 u + 700
= 8 u + 700

8 u + 700 = 3700
8 u = 3700 - 700
8 u = 3000

1 u = 3000 ÷ 8 = 375

Number of stickers in the 3rd packet
= 4 u + 700
= 4 x 375 + 700
= 1500 + 700
= 2200

Answer(s): 2200