2500 stickers are in 3 packets.
The 1st packet has 700 stickers more than the total number of stickers in the 2nd and 3rd packets.
The 3rd packet has 2 times as many stickers as the 2nd packet.
How many stickers does the 1st packet contain?
Choose the packet with the least stickers to be 1 u.

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

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

Number of stickers in the 1st packet = 3 u + 700

Total number of stickers
= 1 u + 2 u + 3 u + 700
= 6 u + 700

6 u + 700 = 2500
6 u = 2500 - 700
6 u = 1800

1 u = 1800 ÷ 6 = 300

Number of stickers in the 1st packet
= 3 u + 700
= 3 x 300 + 700
= 900 + 700
= 1600

Answer(s): 1600