[問題] GWD 4-37

[pipson]

If an automobile averaged 22.5 miles per gallon of gasoline, approximately how many kilometers per liter of gasoline did the automobile average?(1 mile = 1.6 kilometers and 1 gallon = 3.8 liters, both rounded to the nearest tenth.)
(A) 3.7
(B) 9.5
(C) 31.4
(D) 53.4
(E) 136.8

我是這麼想
x(miles) / y(gallon) = 22.5(miles per gallon)
1.6x(kilometers) / 3.8y(liters) = 22.5
x(kilometers) / y(liters) = 22.5 * (3.8/1.6) = 53.43
所以選(D)
結果答案是(B)
何解???????????????

[micki]

22.5 * 1.6 / 1 * 3.8 = 9.5 km/liter

分母 *16 把單位換成km
分子 *3.8 把單位換成liter

[huacy]

22.5 miles/gallon * 1.6 kilometers/mile * 1/3.8 gallon/liter ~= 9.5 kilometers/liter

同顏色的單位相消, 這類問題 只要最後的單位正確就行了

[pipson]

原來如此
多謝高手們指點