Roger will flip a coin 3 times. Which 2 events are disjoint?

Mathematics

1 answer:

Ganezh [65]3 years ago

7 0

Answer: D. Getting at least 2 heads and Getting at least 2 tails

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Explanation:

Choice A is not disjoint because "getting at least 1 tail" could have the sequence TTH. We see that we have two tails and exactly one head. So the events "getting exactly 1 head" and "Getting at least 1 tail" are possible to occur at the same time; therefore, they aren't disjoint events. Disjoint events are two events that cannot occur simultaneously. An example would be flipping heads and tails on the same coin at the same time.

Choice B is also not disjoint. We could have the sequence THT, which has at least one head and at least one tail. "At least" means that amount or more.

Choice C is also not disjoint. We could have the sequence HTT. This has exactly one head and at least two tails.

Choice D is the only thing left. It must be the answer. It is not possible to get 2 heads and 2 tails when Roger only flips the coin 3 times. He would need to flip the coin at least 4 times for this to happen. The portions "at least" don't even need to be considered. So this shows how choice D is disjoint.

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Lines l and k are parallel to each other. A=120 degrees. and C=80 degrees. What is the number of degrees in B??

Aleonysh [2.5K]

Answer:

B = 160°

Step-by-step explanation:

This is how I solved it (I hope the explanation isn't too confusing):

Since L and K are parallel, I drew a straight line from A to B. By doing this, I'm making a triangle: ΔABC

Then I solved for the angles of the triangle. First, we are given that ∠C = 80° and ∠A = 120°. Although, when I drew the vertical line from A to B, it made a 90° (see attachment).

So what we basically did was break ∠A into two parts: an angle inside ΔABC and one outside. To find the interior angle, simply subtract 90° from 120° to get 30°.

There are 180° in a triangle, so add the two interior angles you know:

30° + 80° = 110°

Then subtract 110° from 180° to find the final interior angle which is:

180° - 110° = 70°.

To find the measure of angle B, you must add all of the parts together, so the 90° outside angle and the 70° interior angle:

90° + 70° = 160°