Looking at number 4, you first have to look at the information that you have:
On tuesday he practiced for 1 5/6 hrs
Monday he practiced for 7/10 hrs
He is supposed to practice for 1 1/4 hr.
You could write questions like:
How much more did Marco practice on Tuesday than he is supposed to practice?
This works because it does indeed involve subtraction, you would be subtracting the amount that he should have practiced from the amount of time that he did practice.
If I didn't answer the question, please message me and I will clarify!
Answer:
The probability that they purchased a green or a gray sweater is 
Step-by-step explanation:
Probability is the greater or lesser possibility of a certain event occurring. In other words, probability establishes a relationship between the number of favorable events and the total number of possible events. Then, the probability of any event A is defined as the quotient between the number of favorable cases (number of cases in which event A may or may not occur) and the total number of possible cases. This is called Laplace's Law.

The addition rule is used when you want to know the probability that 2 or more events will occur. The addition rule or addition rule states that if we have an event A and an event B, the probability of event A or event B occurring is calculated as follows:
P(A∪B)= P(A) + P(B) - P(A∩B)
Where:
P (A): probability of event A occurring.
P (B): probability that event B occurs.
P (A⋃B): probability that event A or event B occurs.
P (A⋂B): probability of event A and event B occurring at the same time.
Mutually exclusive events are things that cannot happen at the same time. Then P (A⋂B) = 0. So, P(A∪B)= P(A) + P(B)
In this case, being:
- P(A)= the probability that they purchased a green sweater
- P(B)= the probability that they purchased a gray sweater
- Mutually exclusive events
You know:
- 8 purchased green sweaters
- 4 purchased gray sweaters
- number of possible cases= 12 + 8 + 4+ 7= 21
So:
Then:
P(A∪B)= P(A) + P(B)
P(A∪B)= 
P(A∪B)= 
<u><em>The probability that they purchased a green or a gray sweater is </em></u>
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Answer: positive
Step-by-step explanation: it’s positive because if you multiply two negative numbers they cancel each other out and it makes a positive number
I think it’s D, hope that helps
Answer:
The tree diagram is shown in the tree diagram is shown.
If the probability to hit is 0.7, then the probability to miss is 0.3.
P(hit, hit) = 0.7*0.7 = 0.49
P(hit, miss) = 0.7*0.3 = 0.21
P(miss, hit) = 0.3*0.7 = 0.21
P(miss, miss) = 0.3*0.3 = 0.09