The Brooks family and the Kim family both used their sprinklers last summer. The water output rate for the Brooks family sprinkler was 40 L per hour. The water output rate for the Kim family sprinkler was 30 L per hour. The families used their sprinklers for a combined total of 55 hours, resulting in a total output of 1900 L. How long was the sprinkler used.

Step-by-step explanation:

Let B be the time the Brooks sprinklers were on, and K be that of the Kims'. Then:

B + K=55

40B + 30K=1900

Solve for B and K

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

11

step-by-step explanation:

32.50-7.50=25

225/25=11