Amount of Bacteria - OG12 PS Q 81

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 25
Joined: Mon Jul 11, 2011 1:13 pm
Followed by:1 members

Amount of Bacteria - OG12 PS Q 81

by tanyasethi » Wed Jul 27, 2011 1:23 am
I know this question has been already answered in the forums, but I didn't quite understand the explanation. So here goes.

Consider below info to be a table:
AMOUNT OF BACTERIA
TIME - AMOUNT
1PM - 10gms
4PM - x gms
7PM - 14.4 gms

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

A. 12.0
B. 12.1
C. 12.2
D. 12.3
E. 12.4

The OA is A
Source: — Problem Solving |

Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 am
Location: India
Thanked: 375 times
Followed by:53 members

by Frankenstein » Wed Jul 27, 2011 1:37 am
Hi,
Let the factor by which the number increase be p
So, x= 10p and 14.4 = x.p
So, 14.4 = x.(x/10) =>x^2 = 144 =>x=12

Hence, A
Cheers!

Things are not what they appear to be... nor are they otherwise

Junior | Next Rank: 30 Posts
Posts: 25
Joined: Mon Jul 11, 2011 1:13 pm
Followed by:1 members

by tanyasethi » Wed Jul 27, 2011 2:29 am
wow got it. Thanks!