Answer:
The temperature yesterday was 36 °C.
Step-by-step explanation:
I am going to solve this question building a system of equations.
We have that:
x is the temperature last week at the lake.
y is the temperature yesterday at the lake.
Last week at the lake it was 23 °C.
This means that [tex]x = 23[/tex]
Yesterday it was 13 degrees warmer.
This means that
[tex]y = x + 13[/tex]
Since [tex]x = 23[/tex]
[tex]y = 23 + 13 = 36[/tex]
The temperature yesterday was 36 °C.