Question

Problem 8

Answer 1

Answer:

Explanation:

1. x represent the copybook while y represent the pen that is bought.

2. 2x + 3y = 9000 means that in order to buy 2 copybooks and 3 pen you have to pay 9000 LL.

3. Solve for the price of x and y

2x + 3y = 9000 (1)
4x + 2y = 8000 (2)

Multiply (1) by -2:

-2(2x + 3y = 9000)
4x + 2y = 8000
——————————
-4x - 6y = -18000
4x + 2y = 8000
—————————
-4y = -10000
y = -10000/-4
y = 2500

Substitute y value into (2):

4x + 2(2500) = 8000
4x + 5000 = 8000
4x = 3000
x = 3000/4
x = 750

Therefore, 1 copy book = 750LL and 1 pen = 2500 LL