Henry received $500 for his birthday which he intends to invest in an account that pays simple interest at the rate of 12% per year. How much will be in the account

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance