How many combinations of 4 students can a teacher choose from 30 students? a. 27,405 b. 120 c. 657,720 d. 810,000

Afruit stand has to decide what to charge for their produce. they need $10 for 4 apples and 4 oranges. they also need $15 for 6 apples and 6 oranges. we put this information into a system of linear equations. can we find a unique price for an apple and an orange?

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?

Emily is entering a bicycle race for charity. her mother pledges $0.90 for every 0.75 mile she bikes. if emily bikes 18 miles, how much will her mother donate?