[求助]涛涛GWD2-23

lingdangyour

AMOUNT OF BACTERIA PRESENT

Time	Amount
1:00 P.M.	10.0 grams
4:00 P.M.	x grams
7:00 P.M.	14.4 grams

 

Data for a certain biology experiment are given in the table above.  If the amount of bacteria present increased by the same
   fraction during each of the two 3-hour periods shown, how many grams of bacteria were present at 4:00 P.M.?

 

A.     12.0

B.     12.1

C.     12.2

D.     12.3

E.      12.4

答案是A。

请问一下，by the same fraction是什么意思？谢谢！

marinezhenger

顶

为什么不是10（1+X）（1+X）=14。4

increased by the same fraction是什么意思？什么时候是乘1+X，什么时候是X

hedongshi

 乘(1+X)或X都是可以的，乘什么到后面就用10去乘那个数

by the same fraction 应该是说每3个小时增加的百分数都相同

marinezhenger

upupup

我想问一下，这个题为什么不是10（1+X）（1+X）=14。4

increased by the same fraction是什么意思？什么时候是乘1+X，什么时候是X

谢谢解答

forgetviviva

10*x*x=14.4

x=1.2

thus at 4:00pm, there are 10*x=12 grams