An auto mechanic charges $50 to diagnose a problem and $25 per hour to repair the problem. if x represents the total number of hours worked and y represents the total charges, which equation represents this situation?

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.