The number of calories burned at the gym is normally distributed with a mean of 425 and a standard deviation of 51. find the z-scores for each data value.

Unfortunately, you failed to include here the data in which the values of the z-scores are to be determined. it can be calculated through the equation,
                                   z-score = (data - mean) / standard deviation

For example, the amount of calorie you burnt is only 450, your z-score would be,
                                   z-score = (450 - 425) / 51 = 0.49

The household makes $424.45