Help with word problem

Question

The James family and the Robinson family each used their sprinklers last summer. The water output rate for the James family sprinkler was 20 L per hour. The water output rate for the Robinson family sprinkler was 25 L per hour .The families used their sprinkler for a combined total of 55 hours,resulting in a total water output of 1275 L. How long was each sprinkler used?

Answer 1

James : x hrs

Rob: y hrs

x+y = 55..............eqn (1)

20 x + 25 y = 1275..............eqn (2)

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20 (55-y) +25 y =1275

solve for y, substitute value of y back in eqn 1

James : x hrs = 20 hrs

Rob: y hrs = 35 hrs