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Nutka1998 [239]

2 years ago

12

In a class of 50 student,18 offered mathematics, 21 offered chemistry while 16 offered biology, 7 student offered mathematics an

d biology, 9 student offered chemistry and biology while 5 student offered the three subjects. find the number that offered mathematics but neither chemistry nor biology.
b the number of students that offered biology but neither chemistry nor mathematics and the number that offer biology neither mathematics nor chemistry

2 answers:

Gekata [30.6K]2 years ago

8 0

Answer:

not wrth aswering

Step-by-step explanation:

alex41 [277]2 years ago

7 0

Answer:

ill try:

18 - 7 = 11

11 - 5 = 6

<u>6 offered math but neither chem nor bio.</u>

16 - 7 = 9

9 - 9 = 0

0 - 5 = -5

<u>so 0 offered bio but neither chem nor math.</u>

<u></u>

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Amiraneli [1.4K]

Answer:

C) The solution for the given system of equations are A(0,-5) and B(-4,3)

Step-by-step explanation:

The given system of equation are : $x^{2} + y^{2} = 25\\2x + y = -5$

from equation 2, we get y = -5 - 2x .

Put the above value of y in the equation (1).

We get: $x^{2} + y^{2} = 25 \implies x^{2} + (-5-2x)^{2} = 25$

By ALGEBRAIC IDENTITY:

$(a+b)^{2} = a^{2} + b^{2} + 2ab\\ (-5-2x)^{2} = (-5)^{2} + (-2x)^{2} + 2(-5)(-2x)$

or, $x^{2} + (-5-2x)^{2} = 25 \implies x^{2} + (25 + 4x^{2} + 20x) = 25$

or, $5x^{2} + 20x = 0 \implies x(5x + 20) = 0$

⇒ x = 0 or, x = -20/5 = -4

So, the possible values for x are: x = 0 or x = -4

If x = 0, y = -5-2x = -5-2(0) = -5

and if x = -4, y = -5 -2(-4) = -5 + 8 = 3

Hence, the solution for the given system of equations are A(0,-5) and B(-4,3)

8 0

2 years ago

Find the area of the given figure :

lawyer [7]

Answer:

formula for area is length × height

so we have 13+8 ×16+4

21×20 = 420m

7 0

2 years ago

A square piece of paper has an area of x2 square units. A

Dmitry_Shevchenko [17]

Answer:

Length of rectangular strip = 12

area of rectangular strip = 2*12 = 24

Area of square = x^2 = 12^2 = 144

Step-by-step explanation:

Area of square x^2

area of rectangle is given by length * width

Length of rectangular strip = x

width of rectangular strip = 2

area of rectangular strip = length * width = 2*x = 2x

Area of square piece of paper when rectangular strip is taken away from it

= Area of square - area of rectangular strip

= $x^2 -2x$

It is given that Area of square piece of paper when rectangular strip is taken away from it is 120 square units.

Thus,

$x^2 -2x = 120\\=> x^2 -2x -120 = 0\\=> x^2 -12x +10x-120\\=> x(x-12) +10(x-12)\\=> (x+10)(x-12) = 0\\\\$

Thus,

either x+10 = 0 or x -12= 0

x = -10 or x = 12

but length cannot be negative hence neglecting x = -10

hence value of x is 12.

Hence,

Length of rectangular strip = 12

area of rectangular strip = 2*12 = 24

Area of square = x^2 = 12^2 = 144

5 0

2 years ago

A stained glass window is going to be installed in a semi-circular opening, which is above a 30 inch wide door. If the stained g

xenn [34]

The answer is <span>$494.55</span>

Let's first imagine a circle and calculate its area and then reduce it in half for the area of a semi-circle. Since this opening is above <span>a 30-inch wide door, the circle will have a diameter of 30 inches.
The area of the circle (A) is:
A = </span>π · r²
where:
π = 3.14
r - radius: r = diameter ÷ 2 = 30 ÷ 2 = 15 inches

So, the area of the circle is:
A = π · r² = 3.14 · 15² = 706.5 inches²

The area of the semicircle is half of the area of the circle:
A1 = A ÷ 2 = 706.5 ÷ 2 = 353.25 inches²

Since the stained glass window costs $1.40 <span>per square inch, for 353.25 square inches it will cost $494.55:
353.25 square inches * 1.40 $/square inch = $494.55</span>

4 0

2 years ago

A statue is mounted on top of a 21 foot hill. From the base of the hill to where you are standing is 57feet and the statue subte

AleksandrR [38]

Please find the attached diagram for a better understanding of the question.

As we can see from the diagram,

RQ = 21 feet = height of the hill

PQ = 57 feet = Distance between you and the base of the hill

SR= h=height of the statue

$\angle SPR$ =Angle subtended by the statue to where you are standing.

$\angle x=\angle RPQ$ = which is unknown.

Let us begin solving now. The first step is to find the angle $\angle x$ which can be found by using the following trigonometric ratio in $\Delta PQR$ :

$tan(x)=\frac{RQ}{PQ} =\frac{21}{57}$

Which gives $\angle x$ to be:

$\angle x=tan^{-1}(\frac{21}{57})\approx20.22^{0}$

Now, we know that $\angle x$ and $\angle SPR$ can be added to give us the complete angle $\angle SPQ$ in the right triangle $\Delta SPQ$ .

We can again use the tan trigonometric ratio in $\Delta SPQ$ to solve for the height of the statue, h.

This can be done as:

$tan(\angle SPQ)=\frac{SQ}{PQ}$

$tan(7.1^0+20.22^0)=\frac{SR+RQ}{PQ}$

$tan(27.32^0)=\frac{h+21}{57}$

$\therefore h+21=57tan(27.32^0)$

$h\approx8.45 ft$

Thus, the height of the statue is approximately, 8.45 feet.

3 0

2 years ago