If the unit selling price is $2.50 and the unit cost is $1.00, what action is needed to maintain the gross margin percentage when unit cost increases $0.25?

Aquadratic function f(x) has a turning point at (3,-7). what is the turning point of -f(x)?

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?

Math it's appreciated. (picture provided)