Let x represent the dollar amount spent on supermarket impulse buying in a 10-minute (unplanned) shopping interval. Based on a newspaper article, the mean of the x distribution is $46 with an estimated standard deviation of $8.

What is the dollar amount spent that separates the bottom 91% from the top 9%? (Round to 2 decimal places)

What is the probability that an impulse buyer spends more than $43.50? (Round to 4 decimal places)

What is the probability that an impulse buyer spends between $42.50 and $50? (Round to 4 decimal places)

What is the probability that an impulse buyer spends less than $40? (Round to 4 decimal places)