What is 15/4 as a decimal?

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

Ftara spends $219 a month for her car payment and she makes $3,200 a month, what percent of her monthly income is spent on her car payment?