The heights of american men aged 18 to 24 are approximately normally distributed with a mean of 68 inches and standard deviation of 2.5 inches. Half of all young men are shorter than?

how do I figure this out?

The given says the height distribution is normally distributed with the mean height equal to 68 inches. In this case, the bell-shaped curve has a vertical symmetry at 68 inches. This means, half of the mean exceeds 68 inches while the other half has height below 68 inches.

A normal distribution is symmetrical about the mean. Therefore half of all young men are shorter than 68 inches.