Answer: the length of the first piece is 35 inches.
the length of the second piece is 105 inches.
the length of the third piece is 210 inches.
Explanation:
Let x represent the length of the first piece.
Let y represent the length of the second piece.
Let z represent the length of the third piece.
The second piece must be 3 times as long as the first one. This means that
y = 3x
x = y/3
The third piece must be twice as long as the second. This means that
z = 2y
The student has 350 inches of wire to make the three pieces. This means that
y/3 + y + 2y = 350
Cross multiplying by 3, it becomes
y + 3y + 6y = 1050
10y = 1050
y = 1050/10
y = 105
x = y/3 = 105/3
x = 35
z = 2y = 2 × 105
z = 210