Question

John buys two types of tree saplings. One starts out at 40 cm and will grow 10 cm every three months. The other sapling starts at 20 cm and will grow 10 cm every two months. After how many months will they be the same height, and how tall will they be? solve for y and x

Answer 1

They will at the same height of 80cm at 12 months.

Explanation:

Sapling A:

y = 10/3x + 40

Sapling B:

y = 5x + 20

Set the equations to equal each other.

10/3x + 40 = 5x + 20

10/3x - 5x = 20 - 40

10x - 15x = 60 - 120

-5x = -60

x = 12

Sub x = 12 into one of the two equations (It doesn't matter which one you choose)

y = 5(12) + 20

y = 80