In a laboratory, the number of bacteria in a certain experiment increases at the rate of 2.5% per hour. Class 8

In a laboratory, the number of bacteria in a certain experiment increases at the rate of 2.5% per hour. Class 8

Question 1.

In a laboratory, the number of bacteria in a certain experiment increases at the rate of 2.5% per hour. Find the number of bacteria at the end of 2 hours if the initial count is 5,06,000. Class 8

Solution:

Number of bacteria at the end of

2 hours = 506000[latex]\left(1+\frac{2.5}{100}\right)^2[/latex]

= 506000[latex]\left(1+\frac{25}{1000}\right)^2[/latex]

= 50600 (1.025)²

= 506000 × 1.025 × 1.025

= 531616 (approx.)

Question 2.

You have won a contest. The organisers offer you two options to choose from :

Option A : You deposit ₹ 100 and you get back ₹ 300.

Option B : You deposit ₹ 1000 and you get back ₹ 1500.

What is the percentage gain each option gives? You can choose any option only once. Which option would you choose? Why? Class 8

Solution:

Option A : Gain = ₹ 300 - ₹ 100

= ₹ 200

So; percentage gain = 200%

Option B : Gain = ₹ 1500 - ₹ 1000

= ₹ 500

So, percentage gain = [latex]\frac{500}{1000}[/latex] × 100

= 50%

So, we should choose Option A.