Find the lateral area of a square pyramid with a slant height of 22m and a base length of 8m

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Can someone me and plz do the problem

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2