Question

Question #112a0

Answer 1

The Lopez sprinkler was used for `15` hours.
The Flores sprinkler was used for `20` hours.

Explanation:

Let
`color(white)("XXX")L` be the number of hours the Lopez sprinkler was used, and
`color(white)("XXX")F` be the number of hours the Flores sprinkler was used.

We are told:
[1]`color(white)("XXX")40L+25F=1100`
[2]`color(white)("XXX")L+F=35color(white)("XX")rarrcolor(white)("XX")L=35-F`

[2] implies that
[3]`color(white)("XXX")40L=1400-40F`

Combining [3] with [1], we have
[4]`color(white)("XXX")1400-40F+25F=1100`

Simplifying
[5]`color(white)("XXX")-15F=-300`
or
[6]`color(white)("XXX")F=30`

If `F=20` and `L=35-F`
`color(white)("XXX")L=15`