The morgan famili and the alexander family each ised their sprinkles last summer. the water output was 20. l per hour. the water output rate for the alexander family ‘s sprinkler was 40 l per hour. the families used their sprinklers for a combined total of 50 hours, resulting in total water output of 1400 l. how long was each sprinkler used?

number of hours  Alexander family ‘s sprinkler work = 20

number of hours  Morgan family ‘s sprinkler work = 30

Step-by-step explanation:

Given in the question,

water output rate for the Alexander family ‘s sprinkler = 40 L  

water output rate for the Morgan family ‘s sprinkler = 20 L

Suppose, number of hours  Alexander family ‘s sprinkler work = x

Suppose, number of hours  Morgan family ‘s sprinkler work = y

Equation1

x + y = 50

Equation 2

40x + 20y = 1400

x = 50 - y

Put this value of x in equation 2

40(50-y) + 20y = 1400

2000 - 40y + 20y = 1400

-20y = 1400 - 2000

-20y = -600

y = 30

Put this value of y in equation 1 to get the value of x

x + 30 = 50

x = 50 - 30

x = 20

expression #3 is not equivalent. the others are.