Sat/act practice

Question

Jason worked 20 hours at $5 per hour and 30 hours at $6 per hour. What was his average hourly wage?

Answer 1

You would use what is know as a "weighted average" to compute the overall average.

The general formula for a weighted average of two samples of sizes n1 and n2 and means x1 and x2 is:

(n1 * x1 + n2 * x2) / (n1 + n2)

In our problem x1=5, x2=6, n1=20, n2=30, so the weighted average is:

(20 * $5 + 30 * $6)/(20 + 30) = $5.60