Can someone explain how to answer this

Pat listed all the numbers that have 15 as a multiple write the numbers in pats list

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

If t8 = 4 and t12 = −2, find the first three terms of the arithmetic sequence.