Can someone please help me with this

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

Look at arnold's attempt to solve the equation for b: 3b = 12 b = 3 · 12 b = 36 describe the mistake that arnold made.

Heather is a cashier. she can ring up 1212 customers in 99 minutes. at this rate, how many minutes does it take her to ring up 44 customers?