70% of the workers at motor works are female, while 68% of the workers at city bank are female. if one of these companies is selected at random (assume a 50-50 chance for each), and then a worker is selected at random, what is the probability that the worker will be female?

69%

Step-by-step explanation:

If Motor Works is selected, the probability that the worker is a female is 70%. If City Bank is selected, the probability is 68%.

But we don't know what company will be selected, we only know that they have the same probability, 50-50.

So, with 50% of probability the worker will be female with a 70% of probability (because they selected from Motor Works) and with 50% of probability the worker will be female with a 68% of probability (they selected from City Bank).

We express this as 50%*70% + 50%*68% = 69%

The multiplication means that both probabilities happen together and the sum means that happens one thing or the other (they select Motor Works or City Bank)

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer