How do I solve this?

Question

Rhoda, an online seller earned Php25,000 as profit. After 2 years, her profit grew to Php56,000. How many years will it take for her to have an income of Php350,000 if her financial growth is exponential?

Answer 1

Use the growth formula

A = A₀e^kt

Solve for k

k = ln(A/A₀)/t --> k=ln(56000/25000)/2

A = 25000e^ln(56/25)t/2 = 25000(56/25)^t/2

Solve for t

t = 2ln(350000/25000)/ln(56/25) = 2ln(14)/ln(56/25)

I'll let you do the arithmetic

Substitute the answer into 25000(56/25)^t/2 to verify