1 unit of electricity

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1 unit of electricity

by sanju09 » Tue Feb 24, 2009 4:24 am
The cost of 1 unit of electricity during a 4 year period is given below.

Year 1, $1 per unit.

Year 2, $1.5 per unit.

Year 3, $1.2 per unit.

Year 4, $2 per unit.

If a factory spent equal dollars each year for electricity what was the average cost of a unit of electricity during the 4 year period?

A. $ 1.333

B. $1.250

C. $1.425

D. $1.175

E. $1.500
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by bluementor » Tue Feb 24, 2009 4:44 am
Assuming x dollars spent each year.

Total consumption for the 4 year period:
=x/1 + x/1.5 + x/1.2 + x/2
=x + 2x/3 + 5x/6 + x/2
=3x/2 + 3x/2
=3x

Total spent for the 4 year period = 4x

Therefore, average unit cost for the 4 year period
= Total spent/ Total consumption
=4x/3x
=$1.333 per unit.

Choose A