4) Ellen deposited $2,500 into a savings account that earns 5% interest per year. Her friend's
bank offers a 6 1/2% annual interest rate. How
much more money would Ellen's money have
earned in one year if she had deposited her
money at her friend's bank?
A) $12.50
B) $32.50
C) $16.25
D) $37.50

How to do this , and can some one explain

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%

Which situation can be modeled by the inequality 5 + 10w ≥ 45? a. you start with $5 and save $10 a week until you have at least $45. b.you start with 5 baseball cards and purchase 10 cards every week until you have at most 45 cards. c.you start with 5 water bottles and purchases cases of 10 water bottles each until you have a total of 45 water bottles. d.you spend $5 plus $10 per week until you have less than $45.