A store sells jump ropes . Each jump rope costs the same amount . During a sale , the store reduces the price of each jump rope by $1.90. Marc spends $12.78 on 2 jump ropes at the sale price. What was the price of 1 jump rope before the sale?

Which is the graph of the function y=2(4)^x

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Anyone know these questions? i need ,.