Given that 220 =-2 and 250 = -1, which of the following do you know?
The variance is 10.
The standard deviation is 30.
The mean is 80.
The median is 40.
The data point x = 20 is 2 standard deviations from the mean.
The data point x = 50 is 1 standard deviation from the mean.
The data point x = 45 has a z-value of 1.5.