请教OG11-86

redemptioner

86.In an increasing sequence of 10 consecutive intergers, the sum of the first 5 integers is 560. What is the sum of the last 5 integers in the sequence?

A.585   B.580   C.575    D.570    E.565  答案A

算不出来，请大家帮忙，谢谢！

redemptioner

thanks  a  lot @!!!!!!!!!

assurance

x,x+1,x+2,x+3,x+4,x+5,x+6,x+7,x+8,x+9.

x+(x+1)+(x+2)+(x+3)+(x+4)=560

(x+5)+(x+6)+(x+7)+(x+8)+(x+9)=560+5*25=585