Question

During one month, 4/10 of Lake Okeechobee is covered in a harmful algal bloom. By the next month, Lake Okeechobee is 90% covered. By how many times does the algal bloom increase?

Answer 1

If 4/10 of Lake Okeechobee is covered in a harmful algal bloom in the first month, then 6/10 of the lake is not covered in the bloom.

In the second month, if 90% of the lake is covered in the bloom, then 10% of the lake is not covered in the bloom.

Since the amount of the lake that is covered by the bloom increased from 4/10 to 9/10, this is an increase of:

(9/10) / (4/10) = (9/10) x (10/4) = 2.25 times

Therefore, the algal bloom increased by 2.25 times.