What is this? answer quickly please

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Asif spent $745.10 on 13 new file cabinets for his office. small file cabinets cost $43.50 and large file cabinets cost $65.95. write and solve a system of equations to find the number of small cabinets and large cabinets he purchased. determine if each statement is true or false. 1. he purchased 5 small cabinets. true or false 2. he purchased 7 large cabinets. true or false 3. he spent $527.60 on large cabinets. true or false

17 in long 1.3 ft wide and 8in high what is the volume