Question

一道英文数学题,真的不会做,高手帮忙做下,分析下怎么做

a street has a row of 15new houses for sale .the middle house is on the most desirable piece of property and is the most expensive .the second house from one end costs 3000more than the first house ,the third house costs 3000more than the second house and so on up to and including the middle house .the second house from the other end costs 5000more than the first house and the third house costs 5000more than the second house and so on up to and including the middle house .the total of all the houses on the street is 3091000.determine a system of equations and then use elimination to calculate the selling price of the houses at each end of the street ?give a reason for your answer

Answer 1

左边第一间 205600
右边第一间 191600

问题问得是一排15套房子
总价是3091000
中间的最贵
左边依次递增3000
右边依次递增5000

所以
设左边为x，右边为y
x+3000*7=y+5000*7
x+(x+3000)+(x+3000*2).....+(x+3000*7) + y+(5000)....+(y+5000*6)=3091000