Bacteria in a test tube increase at the rate of 0.9% per hour. At 12 noon there are 4500 bacteria.
At 3 pm, how many bacteria will be present?
Give your answer to 3 significant figures.

. (a) A scientist is doing an experiment on bacteria. She finds that the number ofbacteria in a test tube increase at a rate of 0.9% per hour.At 12 noon there are 4500 bacteria.At 3 pm, how many bacteria will be present? Give your answer to 3 significantfigures.

12pm 4500 bacteria1pm 4500 x 1.009 bacteria 2pm 4500 x 1.009 x 1.009 bacteria3pm 4500 x 1.009 x 1.009 x 1.009 bacteriaTherefore at 3pm there are 4620 bacteria present.

4620 (3)(b) In another experiment with the same bacteria, the scientist counts 3000 bacteria.How many bacteria were there two hours prior to this measurement?Give your answer to 3 significant figures.

Now 3000 bacteria1 hour ago 3000 ÷ 1.009 bacteria 2 hours ago 3000 ÷ 1.009 ÷ 1.009 bacteriaTherefore 2 hours ago there were 2950 bacteria present

2950

Step-by-step explanation:

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x