[問題]GWD27-35

[amyliang]

Q35:
The interior of a rectangular carton is designed by a certain manufacturer to have a volume of x cubic feet and a ratio of length to width to height of 3 : 2 : 2. In terms of x, which of the following equals the height of the carton, in feet?

A.3√ x
B.3√ (2x/3)
C.3 √ (3x/2)
D. (2/3) *3√ x
E.(3/2) 3√ x

Ans:B 註:√ =根號...... (不知道看不看的懂)
有沒有人可以告訴我 這是怎麼算出來的啊???

[gary092083]

設 L，W，H 分別為 3y，2y，2y (滿足題目給的比例3:2:2)

體積為LWH= 12y^3 = x (x為題目給的體積值)

移項計算一下： y^3=x/12 => y= 3√(x/12)

因為 H=2y => 2y=2* 3√(x/12) ， 把2移進根號裡變8，與分母12約分，就得答案嚕


希望用打字的看得懂。

[amyliang]

Thank you so much
I forgot to multiple 2 to the H.