How do i label this on the number line?

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!

Me. i can't figure out this question. give an explanation too. .

The function f(x) = 14,600(1.1)* represents the population of a town x years after it was established. what was the original population of the town?