It would be the girls because 7 divided into 21 equally is 3. So there will be 7 groups of 3 girls.
Answer:
DC = 3
Step-by-step explanation:
Based on triangle similarity theorem, we would have the following equation:
Plug in the values
Cross multiply
3(9 + DC) = 9×4
27 + 3DC = 36
Subtract 27 from each side
3DC = 36 - 27
3DC = 9
Divide both sides by 3
DC = 9/3
DC = 3
Using the Empirical Rule, it is found that her finishing time will be between 70 and 82 seconds in 95% of her races.
<h3>What does the Empirical Rule state?</h3>
It states that, for a normally distributed random variable:
- Approximately 68% of the measures are within 1 standard deviation of the mean.
- Approximately 95% of the measures are within 2 standard deviations of the mean.
- Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, the mean is of 76 seconds and the standard deviation is of 3 seconds, then:
76 - 2 x 3 = 70.
76 + 2 x 3 = 82.
Which means that values between 70 and 82 seconds are within 2 standard deviations of the mean, hence the percentage is of 95%.
More can be learned about the Empirical Rule at brainly.com/question/24537145
Answer:
-1
Step-by-step explanation:
2x-y+7
Let x = -5 and y = -2
2(-5) -(-2) +7
-10 +2 +7
-10 +9
-1
solution:
A and B have 26 cards which are 7 spades and 19 non spades.
C and D have 6 spades and 20 non spades.
13 cards are chosen randomly from 26 cards (6 spades and 20 non spades)
probability of choosing exactly 4 spades is given by
(6 / 26) × (5/ 25) × (4/24) × (3 / 23) = 3/2990
