The Pham family and the Morgan family each used their sprinklers last summer. The water output rate for the Pham family's sprinkler was 25L per hour. The water output rate for the Morgan family's sprinkler was 35L per hour. The families used their sprinklers for a combined 65total of hours, resulting in a total water output of 1975L . How long was each sprinkler used?

1/5^2 = 7.56/45

then

a and c

for infinitely many solutions we require both left and right sides to be equal

distribute and simplify

a

14 - 8x = 20 - 8x - 6 = 14 - 8x ← both sides equal so infinite solutions

b

6x - 54 = 6x - 54 + x = 7x - 54 ← not equal

c

4x + 16 = 4x + 10 + 6 = 4x + 16 ← both sides equal so infinite solutions

d

5x - 40 + 10 = 5x + 10

5x - 30 = 5x + 10 ← not equal

the anwser is x< -17/2