一个傻问题lsat-7-16

三脚猫

16.   Comets do not give off their own light but reflect light from other sources, such as the Sun. Scientists estimate the mass of comets by their brightness: the greater a comet’s mass, the more light that comet will reflect. A satellite probe, however, has revealed that the material of which Halley’s comet is composed reflects 60 times less light per unit of mass than had been previously thought.

The statements above, if true, give the most support to which one of the following?

(A) Some comets are composed of material that reflects 60 times more light per unit of mass than the material of which Halley’s comet is composed.

(B) Previous estimates of the mass of Halley’s comet which were base on its brightness were too low.

(C) The total amount of light reflected from Halley’s comet is less than scientists had previously thought.

(D) The reflective properties of the material of which comets are composed vary considerably from comet to comet.（B）

(E) Scientists need more information before they can make a good estimate of the mass of Halley’s comet.

这个问题有点不好意思，想确认一下

Ａreflects 60 times less light than B是指A 放射的光线是Ｂ的近60倍吗？还是说Ａ放射的光线比Ｂ少60倍？

hedonism555

Ａ放射的光线比Ｂ少60倍

hedonism555

Supplementary clarification,

The overall intensity of the observed light undergoes no change. But the ratio between light and mass declined. Say, original thought contemplates that 1 mass reflects 70 light. Now, new observation reveals that 1 mass reflects only 10 light.

Finally, the present observed intensity of light needs much more mass than previously expected to quantitify.  

hedonism555

originally,   1 mass =>  70 light

actually,     1 mass => 10 light

the ratio is transformed from 1 : 70 to 1 : 10.  So, if the constant number of light stays the same, then the constant number of mass must increase to compensate the shrunk ratio.

三脚猫

明白了，斑竹。我忽略了per unit的关系