Answer:
Charlie should use a stopwatch with minutes and seconds
Step-by-step explanation:
charlie should not count in his head as it is not accurate, he could count too fast or slow
Charlie should not look at that clock and the seconds will affect the 25 minutes, whether it be less or more
Charlie should not use an hourglass as he might flip it over too soon or quick and it's not very accurate
therefore using the stopwatch allows him to accurately and fairly keep track of the exact time
Answer: 2x+12
Step-by-step explanation:
2(10)+2(x-4)
20+2x-8
12+2x
<em>Last year the chess club had 30 members. This year the club has 24 members. </em>
Last year, the chess club had 30 members. This year, the club has 24 members. Since this year had less than last year ( 30 > 24), the percent will be decreasing.
To find the percent decrease, you have to use the following formula.

Difference refers to the difference between the two numbers, 24 and 30. The difference between 24 and 30 is 6. Original refers to the original number, which is last year's amount of members in the chess group. Therefore, original = 30.
Substitute the numbers into the formula.

To convert the decimal to a fraction, multiply the decimal by 100.

The answer is the number of chess members decreased by 20%.
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Since I started off by identifying whether it was decreasing or increasing, I did the work a bit differently. When finding the difference, you would usually subtract 30 from 24, which results in -6. Above I used 6, but if you used -6, you would end up with a result of -20%, which means it decreased by 20%. They bot end up with the same result, but you don't always have to first identify whether it's decreasing or increasing.
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Answer:
1
Step-by-step explanation:
Let's start by prime factorizing (finding the prime factors) of 16 and 21:


We can see that they DO NOT have any common factors, meaning that their greatest common factor is 1.