The formula B=40+2w/3 is USed for working out the electricity bill of b-naira for a month, in which W -kilowatt -hour of electricity used.

Question

A:find the bill for a month in which 2430 kilowatt/hour of electricity is used.

B:find the number of kilowatt/hour used by a consumer who receives a bill of #2456.

Answer 1

for a) simply replace w with 2430 and evaluate

in b):
2456 = 40+2w/3
2416 = 2w/3
7248 = 2w
w = 2624