The gcf of 18 and 20 is 2, so your answer is:
2(9+10)
For this problem, the most accurate is to use combinations
Because the order in which it was selected in the components does not matter to us, we use combinations
Then the combinations are 
n represents the amount of things you can choose and choose r from them
You need the probability that the 3 selected components at least one are defective.
That is the same as:
(1 - probability that no component of the selection is defective).
The probability that none of the 3 selected components are defective is:

Where
is the number of ways to select 3 non-defective components from 117 non-defective components and
is the number of ways to select 3 components from 120.


So:

Finally, the probability that at least one of the selected components is defective is:

P = 7.4%
Answer:
4/6 of a pizza.
Step-by-step explanation:
We know that:
Both pizzas are of the same size.
Jasmine cut her's into 12 slices.
Kelly cut her's into 6 slices, and ate 2 slices, then Kelly ate 2/6 of a pizza.
Jasmine ate X of a pizza, and we know that between them ate a total of 1 pizza.
This means that:
X of a pizza + 2/6 of a pizza = 1 pizza
X + 2/6 = 1
X = 1 - 2/6
X = 6/6 - 2/6 = 4/6
Jasmine ate 4/6 of a pizza, knowing that she cut her's into 12 slices, this would mean that she ate 8/12 of a pizza, or 8 slices.