The cost per unit of electricity during a 4 year period is as follows:
Year 1, $1 per unit;
Year 2, $1.5 per unit;
Year 3, $2 per unit;
Year 4, $2.5 per unit.
If a factory spent equal dollars on electricity each year, what was the average cost of a unit of electricity during the 4 year period?	Choose the correct choice from the following.
A) $1.66 B) $1.46 C) $1.36 D) $1.56 E) $1.26
Let money spent each year = $15   Units bought first year = 15   Units bought second year = 10   Units bought third year = 7.5   Units bought fourth year = 6   Total number of units = 38.5   Total money spent = 15*4= 
<gadget id="calculator">15*4</gadget>
<output>60</output>
60   Average= 60/38.5 = 1.56   Answer : $1.56
<result>D</result>
The cost per unit of electricity during a 4 year period is as follows:
Year 1, $1 per unit;
Year 2, $1.5 per unit;
Year 3, $2 per unit;
Year 4, $2.5 per unit.
If a factory spent equal dollars on electricity each year, what was the average cost of a unit of electricity during the 4 year period?