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.