Question

What is the bill of a house that consumed 1000 units of electricity,if the first 100 units are charged $10.00 per unit and the remaining units at $5.00 per unit?

Answer 1

$14500

Explanation:

$10 per unit means 1 unit is equivalent to 10 dollars.

∴Unit multiplier =
`(10 dollars)/(unit)`

$5 per unit means 1 unit is equivalent to 5 dollars

∴Unit multiplier =
`(5 dollars)/(unit)`

Remaining units = 1000 - 100 = 900 units

The unit multipliers are arranged in such a way that the "units” in the numerator and denominator will cancel each other out leaving us with “dollars” in the numerator. Our answer should be expressed in dollars
since the question requires us to calculate the bill

Bill of the House = Charge of first 100 units + Charge of remaining units

= (1000 units)(
`(10dollars)/(unit)`) + [(900)units][
`(5dollars)/(unit)`]

= $10000 + $4500

= $14500