Area of circles, please help me it's so that I can pass this year. Solve it

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

Suppose sat writing scores are normally distributed with a mean of 497 and a standard deviation of 109. a university plans to award scholarships to students whose scores are in the top 2%. what is the minimum score required for the scholarship? round your answer to the nearest whole number, if necessary.

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle