The manager of a fast food restaurant collected data to study the relationship between the number of employees working registers and the amount of time customers waited in line to order. he made a scatter plot of the data and created a trend line with the equation y = -70x + 300, where y is the total amount of time waited in seconds and x is the number of employees working registers. maria went to the restaurant and waited 90 seconds to place her order. use the trendline equation to predict how many employees were working. round to the nearest whole number if necessary.