请教nn一道数学题...谢谢:)

lizhihuantu

A family made a down payment of$ 75 and borrowed the balance on a set of encyclopedias that cost $400.The balance with interest was paid in 23 monthly payments of $16 each and a final payment of $9.The amount of interest paid was what percent of the amount borrowed?
    没理解题目.......答案是16%       

 

trifling

 [16*23-(400-75-9)]/(400-75)=16%

lizhihuantu

能翻译下中文意思不????

主要是没理解题目意思..............谢谢

xianwhartons

題目問利息/借的錢=多少ratio          
這家庭只自己付頭期款75,其他全是借的.所以分母放400-75. The balance with

interest was paid in 23 monthly payments of $16 each and a final payment

of $9.全部付的錢=16*23.要只求利息就要-(400-75-9)