X+4=2x+5
-1=x
hope this helps
A. multiplication is your answer.
Answer:
0.173 probability that she gets exactly three questions correct.
Step-by-step explanation:
For each question, there are only two possible outcomes. Either she guesses the correct answer, or she does not. The probability of guessing the correct answer for a question is independent of other questions. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
Seven questions:
This means that 
Each question has four choices.
Abby guesses, which means that 
Find the probability to the nearest thousandth, that Abby gets exactly three questions correct.
This is P(X = 3).


Solution: 7.5 Degrees per hour
Reasoning: 15/2 is equal to 7 1/2 or 7.5