Question

There are 1,200 bacteria in a lab dish. The number of bacteria decreases by 10% per day. Compare the decrease in the number of bacteria for days 1 to 3 with the decrease for days 4 to 6. Use the drop-down menu to complete the sentence.

What words belong in the blank below?
The number of bacteria decreases at a faster rate than from day 4 to day 6.
A. at a slower rate
B. at the same rate
C. at a faster rate
D. at a higher rate

Answer 1

The number of bacteria decreases at a faster rate from day 4 to day 6 when compared to the decrease for days 1 to 3.

Step-by-step explanation:

The number of bacteria decreases at a faster rate from day 4 to day 6 when compared to the decrease for days 1 to 3.

Let's calculate the decrease for each period:

For days 1 to 3: If there are 1,200 bacteria in the lab dish on day 1, the number of bacteria decreases by 10% per day. So, after day 1, there will be 1,200 - (1,200 x 0.1) = 1,080 bacteria. After day 2, there will be 1,080 - (1,080 x 0.1) = 972 bacteria. And after day 3, there will be 972 - (972 x 0.1) = 875 bacteria.

For days 4 to 6: Starting with 875 bacteria on day 4, the number of bacteria will decrease by 10% per day. So, after day 4, there will be 875 - (875 x 0.1) = 788 bacteria. After day 5, there will be 788 - (788 x 0.1) = 709 bacteria. And after day 6, there will be 709 - (709 x 0.1) = 641 bacteria.

Therefore, the number of bacteria decreases at a faster rate from day 4 to day 6.