Answer:

Step-by-step explanation:
The answer is 160 because as you stated in the question the number of bacteria doubles every five minutes, and after 10 minutes there are 40. Therefore, after 15 minutes there are 80 (40 doubled is 80), and after 20 (another 5 minutes), the number of bacteria is the double of 80, which is 160.
- Hope I helped :)
- PeaceLoveHappiness
It is A because if you subtract 9 and 6 you get 3 and then you add the 4 and get 7
The first column is the ratio you start with. The next column in the table should be the reduced fraction. To properly reduce a fraction, you divide the same number on the top and bottom of the fraction. Melody instead subtracted 1 in the top and bottom of the fraction to reduce it. She should have divided the top and bottom by 2 to get the second column of 1 pound of turkey and 3 people served.
The final column is designed to be the answer to the initial question of how many people are fed by 15 pounds of ground turkey. Starting with column 2 (the reduced ratio of 1/3), multiply the top by 15 to get 15 pounds of ground turkey. Then do the same to the bottom of the fraction. 3 x 15 = 45 people fed.
So the table should have been
Pounds of turkey 2 1 15
People served 1 3 45
Melody's overriding error was in believing that adding or subtracting numbers to both the top and bottom of a ratio/fraction keep its value the same. Instead, only multiplying or dividing the top and bottom by the same number creates an equivalent fraction.
1040 - 650 = 390
By subtracting the cost from the amount she sold the stove for, we can find the profit of $390.
I hope this helps! :)