Answer:
10 months. Each plan will save 800 dollars.
Explanation:
500 + 30x = y
300 + 50x = y
You want the months to give the same amount of money. The x has to be the same for both
500 + 30x = 300 + 50x Subtract 300 from both sides
500 - 300 + 30x = 50x Combine
200 + 30x = 50x Subtract 30x from both sides
200 = 50x - 30x Combine
200 = 20x Divide by 20
x = 10
So in 10 months time the amounts will be the same. How much will there be?
500 + 30*10 = 500 + 300 = 800
300 + 50*10 = 300 + 500 = 800