To find the expected value of the distribution, we multiply each outcome by it's probability. Doing this, we get that the expected value of defects on a skateboard is of
.
Outcomes and probabilities:
0 defects, 9/10 probability
1 defect, 1/20 probability
2 defects, 1/25 probability
3 defects, 1/100 probability.
Expected value:

Dividing both numerator and denominator by 4:

Thus, the expected value of defects on a skateboard is of
.
A similar problem is given at: brainly.com/question/23156292.
4x^2+48x=20
4x^2+48x+144=164
(2x+12).(2x+12)= + 59rt(164)
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Square part of perimeter = 40.
Half circle = 25.135.
Together 65.135 is perimeter.
Area of square: 192
Are of half circle: 100.53.
Together 292.53
Rounded =292.48 I guess, its the most logical option since I don't see it and the only one that fits perimeter answer.
So its the 3rd question I believe, you may want to double check.
Hit the heart if it was helpful.