Answer:
$648.
Step-by-step explanation:
$400+50% = $600
$600+8%=$648
You need to understand that you're solving for the average, which you already know: 90. Since you know the values of the first three exams, and you know what your final value needs to be, just set up the problem like you would any time you're averaging something.
Solving for the average is simple:
Add up all of the exam scores and divide that number by the number of exams you took.
(87 + 88 + 92) / 3 = your average if you didn't count that fourth exam.
Since you know you have that fourth exam, just substitute it into the total value as an unknown, X:
(87 + 88 + 92 + X) / 4 = 90
Now you need to solve for X, the unknown:
87
+
88
+
92
+
X
4
(4) = 90 (4)
Multiplying for four on each side cancels out the fraction.
So now you have:
87 + 88 + 92 + X = 360
This can be simplified as:
267 + X = 360
Negating the 267 on each side will isolate the X value, and give you your final answer:
X = 93
Now that you have an answer, ask yourself, "does it make sense?"
I say that it does, because there were two tests that were below average, and one that was just slightly above average. So, it makes sense that you'd want to have a higher-ish test score on the fourth exam.
Tom parked the car at the garage for 5 hours
Step-by-step explanation:
Let x be the number of hours
Then according to given statement the equation will be:

Dividing both sides by 2

Hence,
Tom parked the car at the garage for 5 hours
Keywords: Linear equation, variables
Learn more about linear equations at:
#LearnwithBrainly
Answer:
Step-by-step explanation:
My answer is 1/6. Here's How I worked it out:
11/21 / 22/7 is the same as or = to 11/21 * 7/22 which = 77/462 and then divide both the numerator and denominator by 77 and you get 1/6. (In other words simplify 77/462). Hope this helped :)