Question

A person hired a firm to build a Cb radio tower. The first charges $100 for labor for the first feet. After that, the cost of the labor for each succeeding 10 feet is $25 more than the proceding 10 feet. That is, the next 10 feet will cost $125, the next 10 feet will cost $150,etc. How much will it cost to build a 90 foot tower? Please explain

Answer 1

9(100) + 25+50 +75+100+125 +150+175+200
or
9(100) +8(25)+ 7(25)+6(25)+5(25)+4(25)+3(25) +2(25) +25
0r
9(100) +36(25)