已知a :b :c = 2 :3 :5 ,a + b + c = 90 ,则 2a – b + 2c =

题目

已知a :b :c = 2 :3 :5 ,a + b + c = 90 ,则 2a – b + 2c =

答案

a :b :c = 2 :3 :5 ,a + b + c = 90
a=90*2/10=18
b=90*3/10=27
c=90*5/10=45
2a – b + 2c
=36-27+90
= 99