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lora16 [44]
3 years ago
5

Five students wrote a mathematics test. The average mark was 68. If the marks for four of the students were 75, 62, 84 and 53, t

he mark of the fifth student was
Mathematics
1 answer:
konstantin123 [22]3 years ago
4 0

Answer:

66

Step-by-step explanation:

Use the formula for the mean of a set of numbers:

                  sum of the numbers

average = --------------------------------

                     count of numbers

Here we know that the average mark was 68, so we can write:

               

                           75 + 62 + 84 + 53 + x

average = 68 = ----------------------------------

                                           5

or                            274 + x

                  68 = -------------------

                                    5

Solving for x, we multiply both sides by 5:     340 = 274 + x.

Subtracting 274 from both sides effectively isolates x:

 340 = 274 + x

- 274    -274

------------------------

  66      =    x

The fifth student's mark was 66.

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4 0
3 years ago
A wire is bent to form a square of side 22 cm. If the wire is re bent to form a circle, its radius is with steps
ExtremeBDS [4]

Step-by-step explanation:

the circumference of a circle is

C = 2×pi×r

with r being the radius.

the square side length is 22 cm. so, the circumference or perimeter of the square (and therefore the length of the wire) is

4×22 = 88 cm.

now, it is the same wire of the same length that is now forming a circle.

so, the circumference of the square is also the circumference of the circle.

therefore,

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5 0
2 years ago
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A tree struck by lightning in a storm breaks and falls over to form a triangle with the ground. The tip of the tree makes a 36°
liraira [26]

Answer: approximately 49 feets

Step-by-step explanation:

The diagram of the tree is shown in the attached photo. The tree fell with its tip forming an angle of 36 degrees with the ground. It forms a right angle triangle,ABC. Angle C is gotten by subtracting the sum of angle A and angle B from 180(sum of angles in a triangle is 180 degrees).

To determine the height of the tree, we will apply trigonometric ratio

Tan # = opposite/ adjacent

Where # = 36 degrees

Opposite = x feets

Adjacent = 25 feets

Tan 36 = x/25

x = 25tan36

x = 25 × 0.7265

x = 18.1625

Height of the tree from the ground to the point where it broke = x = 18.1625 meters.

The entire height of the tree would be the the length of the fallen side of the tree, y + 18.1625m

To get y, we will use Pythagoras theorem

y^2 = 25^2 + 18.1625^2

y^2 = 625 + 329.88

y^2 = 954.88

y = √954.88 = 30.9 meters

Height of the tree before falling was

18.1625+30.9 = 49.0625

The height of the tree was approximately 49 feets

5 0
3 years ago
Line parallel to y=1/2x-5
Sveta_85 [38]

Answer:

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Step-by-step explanation:

6 0
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pychu [463]
No, all parallelograms are not squares because squares have to have all 90 degree angles, while parallelograms don't
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