Logan wants to know how many skateboards have defective parts. He inspects 20,000 skateboards and keeps track of the number of defects per board. Use his probability distribution table to find the expected value for defects on a skateboard.

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:

arrange the equations with like terms in columns.

analyze the coefficients of x or y.

add the equations and solve for the remaining variable.

substitute the value into either equation and solve.

check the solution.

step-by-step explanation: