AMOUNT OF BACTERIA PRESENT
Time Amount
1:00 P.M. 12.0 grams
4:00 P.M. x grams
7:00 P.M. 16.4 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.? Pick one:
A) 12.0
B) 14.0
C) 14.2
D) 12.3
E) 14.4
The question says that bacteria increased by same fraction, not by same amount in 2 intervals of 3 hours.   Let X represent the amount of bacteria present at 4:00 PM. Since the fractional increase must remain constant from 1 to 4pm as it is from 4pm to 7pm:   Fractional increase from 1 PM to 4 PM = X / 12.0   Fractional increase from 4 PM to 7 PM = 16.4 / X   X \ 12 = 16.4 \ X   X^2 = 16.4 * 12   X = 14   answer : 14.0
<result>B</result>
AMOUNT OF BACTERIA PRESENT
Time Amount
1:00 P.M. 12.0 grams
4:00 P.M. x grams
7:00 P.M. 16.4 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.?