Question

The time it takes the population of a microorganism to reduce by half is 0.000027503 of a year. What number is the best estimation of this quantity?(1 point)
Responses

0.01
0.01

0.00002
0.00002

0.00003
0.00003

0.03

Answer 1

A total of 7,803,100 tourists visited Country A from the year 2018 to the year 2020. Round to the nearest place value, then express this number in the form of a single digit times an integer power of 10

Answer 2

Two weeks before an examination day, a librarian monitored the number of students who visited the library. Then they compared it with the number of visits made in an average week. Approximately 2×10 to the power of 3
visits were reflected in their logbook during this two-week period, while only about 5×10 to the power of 2
were reflected on an average week. How many times higher is the number of library visits before examination day compared to the library visits in an average week? Your answer should be a whole number

Answer 3

It takes 10 years for a $100 monthly bank deposit to amount to $15,528.23 when invested at 5% interest compounded monthly. Round to the nearest place value, then express the amount $15,528.23 in the form of a×10 to the power of n
where a
is single digit

Answer 4

To estimate the given quantity of 0.000027503 of a year, we can round it to the nearest significant figures.

The provided options are:
- 0.01
- 0.00002
- 0.00003
- 0.03

Given that 0.000027503 is closest to 0.00003, the best estimation of this quantity is:

**0.00003**

Answer 5

To express the number 7,803,100 in scientific notation, we first round it to the nearest place value, which is 7,800,000.

Next, we express 7,800,000 in the form of a single digit times an integer power of 10:

1. Start with the number: 7,800,000
2. Move the decimal point 6 places to the left (to the left of the 7), which gives us 7.8.
3. Since we moved the decimal 6 places, we multiply by \(10^6\).

Thus, 7,803,100 rounded to the nearest place value and expressed in scientific notation is:

**\(7.8 \times 10^6\)**.

Answer 6

To determine how many times higher the number of library visits before examination day is compared to the average weekly visits, we can use the given values in scientific notation:

- Library visits before examination day: \(2 \times 10^3\)
- Average weekly visits: \(5 \times 10^2\)

First, we need to convert these values to their standard form:

- \(2 \times 10^3 = 2000\)
- \(5 \times 10^2 = 500\)

Now, we can find how many times higher the number of visits before examination day is by dividing the two quantities:

\[
\text{Times higher} = \frac{2000}{500} = 4
\]

Thus, the number of library visits before examination day is **4 times** higher than the average weekly visits.

Answer 7

To express the amount $15,528.23 in the form \(a \times 10^n\) where \(a\) is a single digit, we first convert it into scientific notation.

1. Start with the number: \(15,528.23\).
2. Move the decimal point 1 place to the left to get \(1.552823\).
3. Since we moved the decimal 1 place to the left, we will multiply by \(10^4\) (because 15,528.23 is effectively \(1.552823 \times 10^4\)).

However, for standard scientific notation, we only want one non-zero digit in front of the decimal point.

Now we round \(1.552823\) to one significant digit, which gives us approximately \(1.6\). Thus, we can express:

\[
15,528.23 \approx 1.6 \times 10^4
\]

So, the final expression is:

**\(1.6 \times 10^4\)**.