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Inga [223]
3 years ago
13

John's Mathematics exam mark this year is increased by 5% to 84. Find his Mathematics exam mark

Mathematics
2 answers:
Svet_ta [14]3 years ago
8 0

Answer:

80%

Step-by-step explanation:

Let's call the past exam mark m,

m*105%=84

m*105/100=84

m=84/(105/100)

m=80

Hope this helps!

nadya68 [22]3 years ago
3 0

Answer:

80

Step-by-step explanation:

new value = 84

old value = n

can use percent change formula:  (new value - old value) / old value = 5/100

\frac{84-n}{n} = \frac{5}{100}

cross-multiply (you can simplify 5/100 to be 1/20 first):  20(84 - n) = n

1680 - 20n = n

1680 = 21n

n = 80

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Need help please.
soldier1979 [14.2K]

Answer:

78.5%

Step-by-step explanation:

The area of the square is equal to diameter squared

i.e 4 in × 4 in = 16 square inches

The area of the circle is π × r²

i.e π × 2² = 12.56637061

The percent of the time the point will be in the circle = (Area of the circle) ÷ (Area of the square) × 100

i.e \frac{12.56637061}{16} × 100 = 78.53981631%

And is equal to 78.5% (rounded up to the nearest tenth of a percent)

8 0
3 years ago
Assume that you assign the following subjective probabilities for your final grade in your econometrics course (the standard GPA
rodikova [14]

Answer:

E(X) = 4*0.2 +3*0.5+ 2*0.2 +1*0.8+ 0*0.02= 2.78

So then the best answer for this case would be:

C. 2.78

Step-by-step explanation:

For this case we have the following probabability distribution function given:

Score         P(X)

A= 4.0       0.2

B= 3.0       0.5

C= 2.0       0.2

D= 1.0        0.08

F= 0.0       0.02

______________

Total          1.00

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

If we use the definition of expected value given by:

E(X) = \sum_{i=1}^n X_i P(X_I)

And if we replace the values that we have we got:

E(X) = 4*0.2 +3*0.5+ 2*0.2 +1*0.8+ 0*0.02= 2.78

So then the best answer for this case would be:

C. 2.78

3 0
3 years ago
1. Simplity the following into lowest term <br>3x - 2 - 2x​
Yakvenalex [24]
The answer is X-2 ........
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Taya2010 [7]

The width is 2.5 in. Volume = Length x Width x Height

220 = 8 \times 11 \times x

\frac{220}{8}  = x = 2.5

5 0
3 years ago
kelly is hanging shelves in her closet. She can buy sheleves for $1.25 a foot. Kelly buys one 5-foot shelf and a shelf that meas
alex41 [277]

The 24 inch shelve is 2 feet ( 1 foot = 12 inches)

She bout 7 feet of shelves (5 + 2 = 7)

The total cost for the shelves was 7 x 1.25 = $8.75

She spend an additional 90 so her total spent was 90 + 8.75 = $98.75

Now subtract her total from 100 to find the amount of change:

100 - 98.75 = 1.25

The change was $1.25

8 0
3 years ago
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