I need help please i don’t understand

Ricardo ran the 400 meter race 3 times his fastest time was 54.3 seconds his slowest time was 56.1 seconds if his average time was 55.0 seconds what was his time for the third race

To finance her community college education, sarah takes out a loan for $2900. after a year sarah decides to pay off the interest, which is 4% of $2900. how much will she pay

If the perimeter of the square equals the perimeter of the regular pentagon. each side of a pentagon is 16cm long. how long is each side of the square?