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Inessa [10]
3 years ago
5

Tammy has scored 82, 78, and 93 on her previous three tests. What score does she need on her next test so that her average (mean

) is 81?
Mathematics
1 answer:
Lyrx [107]3 years ago
5 0

Answer:

She needs a grade of 71 on her next text.

Step-by-step explanation:

Mean of a data-set:

The mean of a data-set is the sum of all values in the data-set divided by the number of values.

Tammy has scored 82, 78, and 93 on her previous three tests.

Thus, her grades are 82, 78, 93 and x, in which x is her grade in the fourth test.

There are 4 tests.

What score does she need on her next test so that her average (mean) is 81?

We have to find x when the mean is 81. So

\frac{82 + 78 + 93 + x}{4} = 81

253 + x = 324

x = 324 - 253

x = 71

She needs a grade of 71 on her next text.

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3. A regular pentagon has a perimeter of 10x + 15. What is the length of che side?
Ivan

Answer:

C

Step-by-step explanation:

A pentagon has 5 sides. Given that it is a regular pentagon, these 5 sides are equal.

The perimeter is the total length of all the sides of the pentagon. Since these 5 sides are all equal, we can divide the perimeter by 5 to obtain the length of a side of the pentagon.

Perimeter= 10x +15

Length of each side

= (10x +15) ÷5

= 2x +3

5 0
3 years ago
10.5125 rounded to the nearest cent plz help me ty <3
Phoenix [80]

Answer: your answer should be 10.5130

Step-by-step explanation:

5 0
2 years ago
Write 87.5% as a fraction in simplest form
Len [333]
87 1/2 is the answer. hope it help.
6 0
3 years ago
120 books increased by 55%
Novay_Z [31]

<span> To find 55% of 120 books, multiply 120 x .55  
Then add that answer to the original 120.</span>

120 + 55% = 186

6 0
3 years ago
Kristen has 64 coins in her bank. She has $9.25 in dimes and quarters. How many dimes and quarters does she have?
Stella [2.4K]
D= # of dimes
q= # of quarters

QUANTITY EQUATION:
d + q= 64

COST EQUATION:
0.10d + 0.25q= $9.25


STEP 1:
multiply quantity equation by -0.10 to be able to eliminate the d term in step 2

(-0.10)(d + q)= (-0.10)(64)
-0.10d - 0.10q= -6.40


STEP 2:
add equation from step 1 to cost equation to eliminate the d term and solve for q

Add
0.10d + 0.25q= $9.25
-0.10d - 0.10q= -6.40

0.15q= 2.85
divide both sides by 0.15

q= 19 quarters


STEP 3:
substitute q value in step 2 into either original equation to find d value

d + q= 64

d + 19= 64
subtract 19 from both sides

d= 45 dimes


CHECK:
0.10d + 0.25q= $9.25
0.10(45) + 0.25(19)= 9.25
4.50 + 4.75= 9.25
9.25= 9.25


ANSWER: There are 45 dimes and 19 quarters.

Hope this helps! :)
7 0
3 years ago
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