Question

One number is 800 less than 3 times the other, and their sum is 1,200. Find the numbers. Which of the following equations can be used to solve the problem if the smaller number is x?

Answer 1

4x - 800 = 1200

Step-by-step explanation:

Let the numbers are x and y

By the statement "One number is 800 less than 3 times of other."

y = 3x - 800 ----------(1)

By another statement " Sum of these numbers is 1200."

x + y = 1200

y = (1200 - x)-------(2)

Now put the value of y from equation (2) to equation (1)

1200 - x = 3x - 800

1200 = x + 3x - 800

4x - 800 = 1200

Therefore, 4x - 800 = 1200 is the answer.

Answer 2

I used systems of equations
x=3y-800
x=1200-y

1200-y=3y-800 is my answer. Hope it helps!