Question

A ride-sharing company claims that the cost of rides follows a Normal distribution with a mean of $10.52. After

paying for a ride from this company, a rider reports that his price is in the 85th percentile of all other riders' prices. If
this rider paid $15.93, what is the approximate standard deviation of this company's ride-sharing cost?

Answer 1

$5.20

Explanation:

According to the Z-Score chart, the 85th percentile has a z-score of 1.04 and if you put that in the z-score equation (15.93-10.52)/x=1.04. Solve for x and you get $5.20.