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.
Answer:
first question is 112, second is 336
Step-by-step explanation:
you only need to do is 84÷3/4=112calories
this is one box of cereal state if you want three
box calories just 3×112
Answer:
1
Step-by-step explanation:
x-y+xy=1-1+1*1=0+1=1
Permutation helps us to know the number of ways an object can be arranged in a particular manner. The correct option is D.
<h3>What are Permutation and Combination?</h3>
Permutation helps us to know the number of ways an object can be arranged in a particular manner. A permutation is denoted by 'P'.
The combination helps us to know the number of ways an object can be arranged without a particular manner. A combination is denoted by 'C'.
The example which is an example of permutation is Selecting a first-, second-, and third-place winner at baking.
Hence, the correct option is D.
Learn more about Permutation and Combination:
brainly.com/question/11732255
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Answer:
Weight gain = 84 lb 5 oz
Average weight gain = 6 lb 5 oz
Step-by-step explanation:
lb means pounds
16 oz = 1 pound
Convert the weight to pounds
Weight when she was born = 8 lb. 13 oz
= 8 pounds + 0.8125 pounds
= 8.8125 pounds
Present weight = 93 lb. 5
oz
= 93 pounds + 0.3125 pounds
= 93.3125 pounds
How much has she gained since birth
Weight gain = Present weight - Weight when she was born
= 93.3125 pounds - 8.8125 pounds
= 84.5 pounds
= 84 lb 5 oz
Weight gain = 84 lb 5 oz
what has been her average weight for each year if she is 13 year old
Average weight gain = Weight gain / 13
= 84.5 pounds / 13
= 6.5 pounds
= 6 lb 5 oz
Average weight gain = 6 lb 5 oz
