Compound Interest - Discussion Page For Q.146 | Aptitude Questions and Answers | Aptitude Free Online-Tests | LucentBlackBoard

Home > Arithmetic Aptitude > Compound Interest > Questions and Answers Discussion

The bacteria in a culture grow by 5% in the first hour, get destroyed by 5% in the second hour and again grow b 5% in the third hour. If the count of the bacteria at the end of the third hour is 8.379 * 108 , find the original count of bacteria in the sample.

A.	8*106	B.	8*104
C.	8*107	D.	8*108

Answer and Explanation

Answer:8*108

Explanation:
Let the original count be x. After the 1st hour , the count is x(1+5/100) = 1.05x. After the 2nd hour , the count is 1.05x(1 – 5/100) = 1.05(0.95)x. After the 3rd hour, the count is [1.05(0.95)x]( 1 + 5/100) = (1.05)(0.95) (1.05)x. Therefore, x= 8*108

Comment on this Question
Name:

LucentBlackBoard.com has the web's largest collection of over 15,000 aptitude questions and answers with detailed explanation which include subjects like Arithmetic Aptitude, Logical Reasoning, Verbal Ability, General Knowledge, Programming Skills and more!

Our online education portal provides a unique and standard learning experience for students. We enable the students to prepare for most of the entrance and competitive exams like MBA (MAT, GMAT), Engineering (IIT-JEE, AIEEE, GATE), Employment (IAS, Bank PO, Railway, UGCNET), Civil Services and many more. We bring you the best in education by providing technical excellence and creating innovative solutions. We provide facility for online test preparation that offers 24/7 access to relevant subject matter and relative tests. These test preparations help the students to groom themselves and get prepared before actually facing the examination.