During the last four years, a large truck company purchased diesel at rates of $1.1, $1.4, $1.8 and $2.1 per gallon. What was the mean cost of diesel over the four-year period if the company spends the same amount of dollars on diesel each year?	Choices
A) $2.5  B) $2.55  C) $1.51  D) $3.25  E) $3.0
finding the Harmonic mean here.   HM = 4/(1/12 + 1/14 + 1/18 + 1/21) = 15.07   $1.51
<result>C</result>
During the last four years, a large truck company purchased diesel at rates of $1.1, $1.4, $1.8 and $2.1 per gallon. What was the mean cost of diesel over the four-year period if the company spends the same amount of dollars on diesel each year?