The cost per unit of electricity during a 4 year period is as follows:
Year 1, $0.75 per unit;
Year 2, $1.50 per unit;
Year 3, $2.25 per unit;
Year 4, $3 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:
A) $1.55
B) $1.44
C) $1.66
D) $1.77
E) $1.88
Let money spent each year = $225   Units bought first year = 300   Units bought second year = 150   Units bought third year = 100   Units bought fourth year = 75   Total number of units = 625   Total money spent = 225*4= 
<gadget id="calculator">225*4</gadget>
<output>900</output>
900   Average= 900/625= 
<gadget id="calculator">900/625</gadget>
<output>36/25 = around 1.44</output>
1.44   Answer : $1.44
<result>B</result>
The cost per unit of electricity during a 4 year period is as follows:
Year 1, $0.75 per unit;
Year 2, $1.50 per unit;
Year 3, $2.25 per unit;
Year 4, $3 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?