Okay so let x = the amount of apples that Maria picks.
Andre picks three times as much as Maria, so amount Andre picks = 3x
Jane picks two times as much as Andre, and Andre = 3x
So Jane = 2(3x), = 6x
All of these added together should give 840.
x + 3x + 6x = 840
10x = 840.
x = 84
Therefore, Maria picked 84 pounds of apples
Andre picked 3x = 3 x 84 = 252 pounds of apples.
Jane picked 6x = 6 x 84 = 504 pounds of apples.