Which expression could be used to solve this problem?

bart practices piano every day. first he practices songs for 20 minutes. then he practices scales for 15 minutes. how much time does bart practice piano in 3 days?

a.
3 × (20 – 15)

b.
20 × (15 + 3)

c.
3 × (20 + 15)

d.
20 × (15 – 3)

What is the correlation coefficient for the data? don't forget to turn the diagnoisticon (in the catalog menu of the calculator). r = answer (round to the nearest thousandth)

Analyze the data sets below. data set a 25,25,25,26,26,26,27,28,28,29,30,31,31,32,33,33,34,35,35,35 data set b 25,25,25,26,26,26,26,27,27,27,27,28,28,29,29,30,31,31,32,34 which of the following statement are true? select all that apply. a. data set a is relatively symmetric and data set b is skewed left. b.the means of the data sets are within 3 units from eachother. c.the data sets have the same standard deviation. d.the mean of data set a is 27.95 and the mean of data set b is 30. e. the data set b has a higher standard deviation than data set a. f. the mean and median of data set a are close in value.

1. a parachutist is 800 feet above the ground when she opens her parachute. she then falls at a constant rate of 5 feet per second. select the equation that represents this situation. h = -800t + 5 y = -5x + 800 h = 5t - 800 y = 800x + 5 i need