Explain how to do this i am lost

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

If the tip varies directly with the number of guest which equation represents between the tip,t, and the number of guest,g?

Kate has 50 quarters and dimes. she has a total of $9.80. how many dimes that she have?