During the last four years, a large truck company purchased diesel at rates of $1.2, $1.4, $1.6 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?  Choose the correct choice from the following answers
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 + 1/16 + 1/21) = 15.1   $1.51
<result>C</result>
During the last four years, a large truck company purchased diesel at rates of $1.2, $1.4, $1.6 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?