AMC8 1991

AMC8 1991 · Q21

AMC8 1991 · Q21. It mainly tests Linear equations, Interest / growth (simple).

For every 3° rise in temperature, the volume of a certain gas expands by 4 cubic centimeters. If the volume of the gas is 24 cubic centimeters when the temperature is 32°, what was the volume of the gas in cubic centimeters when the temperature was 20°?

对于每升高3°的温度，某种气体的体积膨胀4立方厘米。如果温度为32°时气体的体积是24立方厘米，那么温度为20°时气体的体积是多少立方厘米？

(A) 8 8

(B) 12 12

(D) 16 16

(E) 40 40

Answer

Correct choice: (A)

正确答案：（A）

Solution

The rate of change is 4 cubic centimeters per 3°. The temperature change is $32° - 20° = 12°$. The corresponding change in volume is $12 \times (4/3) = 16$ cubic centimeters. Thus the initial volume of the gas was $24 - 16 = 8$.

变化速率为每3° 4立方厘米。温度变化为$32° - 20° = 12°$。相应的体积变化为$12 \times (4/3) = 16$立方厘米。因此，初始气体体积为$24 - 16 = 8$。

Topics