题目

#1.Terry invested a total of $4500.A portion was invested at 4% and the rest was invested at 6%.The amount of Terry’s annual return on each portion is the same.Find the average rate of interest Terry earned on the $4500.
#2.In September,Poar Bay Wines had a net revenue of $574.56 from the sale of 3216 new wine bottles less the refund paid for 1824 returned bottles.In October,net revenue was $944.88 from the sale of 5208 bottles less the refund paid on 2232 returned bottles.How much did polar Bay Wines charge per new wine bottle and how much was the refund for each returned bottle?
In checking the petty cash a clerk counts “q”quarters,“d”dimes,“n”nickels,and “p”pennies.Later he discovers that X of the nickels were counted as quarters and X of the dimes were counted as pennies.(Assume that X represents the same number of nickels and dimes.) What must the clerk do to correct the original total?

提问时间：2020-10-17

答案

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