Mike D. answered • 08/07/20

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Azhad

It's an expectation problem.

If you select a scooter at random : probability from A is 500/1000, probability that is standard is 0.90

B 300/1000, 0.92

C 200 / 1000 0.95

So expectation is 0.5 x 0.90 + 0.3 x 0.92 + 0.2 x 0.95 (you can calculate this).

You could also draw a tree diagram. First branch is the plant (3 branches), second branch is the quality (standard/non-standard) and find the probabilities at the end of the 2nd branches, and add together.

Mike

Mike D.

08/07/20