Answer:
The depth of the lake last year was 52 feet
Step-by-step explanation:
Given as :
This year depth of lake = 39 feet
Let the last year depth of lake = x feet
Now,
According to question :
The depth this year is 25% less than that of last year
I.e 39 feet = x - 25% of x
Or, 39 feet = [tex]\frac{75x}{100}[/tex]
or, x = [tex]\frac{3900}{75}[/tex]
∴ x = 52 feet
Hence The depth of the lake last year was 52 feet Answer