Answer: Andre picked 252 lbs of apple
Explanation:
Let x represent the number of pounds of apple that Jane picked.
Let y represent the number of pounds of apple that Andre picked.
Let z represent the number of pounds of apple that Maria picked.
Andre picks 3 times as many pounds as maria. This means that
y = 3z
z = y/3
Jane picks 2 times as many pounds as Andre. This means that
x = 2y
The total weight of the apples 840 ibs. This means that
x + y + z = 840 - - - - - - - - - -1
Substituting z = y/3 and x = 2y into equation 1, it becomes
2y + y + y/3 = 840
Cross multiplying by 3, it becomes
6y + 3y + y = 2520
10y = 2520
y = 2520/10 = 252
x = 2y = 2×252 = 504
z = y/3 = 252/3 = 84