[問題]GWD12-21

[blacklilu]

Color X ink is created by blending red, blue, green, and yellow inks in the ratio 6 : 5 : 2 : 2. What is the number of liters of green ink that was used to create a certain batch of color X ink?
(1) The amount of red ink used to create the batch is 2 liters more than the amount of blue ink used to create the batch.
(2) The batch consists of 30 liters of color X ink.


ANS : D
為啥米A成立呀？

[huacy]

red:blue:green:yellow 比率為 6:5:2:2
假設 yellow 用了2y liters
根據比率 那 red 就用了6y, blue 用了5y
知道 red 比 blue 多了2 liters 就可以算出 y=2

red : 12 liters
blue: 10 liters
green: 4 liters
yellow: 4 liters

[chris8888]

應該是這樣

假設blue是x liters
r:b:g:y
6:5:2:2
(x+2):x:2:2

其中 (x+2) : x = 6:5 => 經過計算得x=10, 其他就可以經過比例算出來了. 如5*2=10, 後面green and yellow都要乘以2