Please help if you can

Tickets to an orchestra concert cost $25.50 apiece plus a & 2.50 handling fee for each order. if jamal spent $79 how many ticket did he purchase

How many different three-digit numbers can be formed using the digits 1 comma 2 comma 9 comma 6 comma 4 comma 3 comma and 8 without repetition? for example, 664 is not allowed.

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).