Answer:
The temperature yesterday was 36 °C.
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
Yesterday it was 13 degrees warmer.
This means that
Since
The temperature yesterday was 36 °C.