1、presume that terry invested x at 4%,and 4500-x at 6%
so x*4%=(4500-x)*6%
x=2700
the total return=2700*4%*2=216
so,the average rate of interest=216/4500*100%=4.8%
2、let x=price of each new bottle,and y=refund paid for each returned bottle
3216*x-1824*y=574.56
5208*x-2232*y=944.88
x=0.19,y=0.02
3、i am not pretty sure about the following conversions
1 dollar = 4 quarters = 10 dimes = 20 nickles = 100 pennies
use these conversions to figure out the result
1 quarter = 5 nickles,so the clerk should cut 4X nickles from the amount
1 diam = 10 pennies,so the clerk should add 9X pennies
and 1 nickle = 5 pennies,less 4X nickles = 20X pennies,then plus 9X pennies
so,the clerk need to cut down 4X*5-9X=11X pennies from the amount to get the correct total