Question

巧算89,91,93,87,88,92,85,93,90,94的平均数

Answer 1

(89+91+93+87+88+92+85+93+90+94)/10
=(87+88+89+90+91+92+93+94+85+93)/10
=[(87+94)*4+(85+93)]/10
=(724+178)/10
=902/10
=90.2