HELP!!!求解GWD一道数学题

sgdittt

答案是C。首先是不理解题意，请赐教！

A certain quantity is measured on two different scales, the R-scale and the S-scale, that are related linearly.  Measurements on the R-scale of 6 and 24 correspond to measurements on the S
-scale of 30 and 60, respectively.  What measurement on the R-scale corresponds to a measurement of 100 on the S-scale?
A.     20

B.     36

C.     48

D.     60

E.   84

sue101

r c有线性关系~

zhongtanlu

R=6时S=30； R=24时S=60； 问R=？时S=100，已知R和S有线性关系：即S=aR+b，讲前面已知条件带入得：

30=6a+b

60=24a+b

连理方程得a=5/3; b=20；即R和S的关系由方程 S=5/3R +20

S=100带入以上方程得R=48

sgdittt

明白了！
感谢童鞋们的得力相助！！！