Answer:
36 runners finished the race.
Step-by-step explanation:
In the first half of the race, 1/4 of them dropped, so we need to calculate 1/4 of 80:
(1/4) * 80 = 80/4 = 20
If 20 runners dropped out, now we have 80 - 20 = 60 runners.
Then, in the second half, 2/5 of the remaining runners dropped out, so:
(2/5) * 60 = 2*60/5 = 120/5 = 24
If 24 runners dropped out, now we have 60 - 24 = 36 runners.
So, 36 runners finished the race.
Answer:
X = 35.7 Y=54.3
Step-by-step explanation:
Let the 2 angles be called X and Y were X is the smaller angle
we know that both angles are complementary therefore
X+Y=90
X = Y - 18.6 ( Given )
Y - 18.6 + Y = 90 ( substitution)
2Y = 90 + 18.6
Y = 108.6/2
Y=54.3
X= Y-18.6= 54.3-18.6 = 35.7
Check : X + Y = 35.7+54.3=90
Answer:
74.86% probability that a component is at least 12 centimeters long.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
Variance is 9.
The standard deviation is the square root of the variance.
So
Calculate the probability that a component is at least 12 centimeters long.
This is 1 subtracted by the pvalue of Z when X = 12. So
has a pvalue of 0.2514.
1-0.2514 = 0.7486
74.86% probability that a component is at least 12 centimeters long.