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3 years ago

5

The ratio of the number of boys and girls in a college is 7:8. If the percentage increase in the number of boys and girls be 20%

and 10% respectively, what will be the new ratio?

1 answer:

DENIUS [597]3 years ago

7 0

Answer:

Step-by-step explanation:

Boys : Girls = 7 : 8

Let the number of boy = 7x

The number of girls = 8x

Number of boys after 20% increase = 120% of 7x

= 1.2 * 7x

= 8.4 x

Number of girls after 10% increase = 110% of 8x

= 1.1 * 8x

= 8.8x

After increase in number of boys & girls = 8.4x : 8.8x

= 84 : 88 { reduce to simplest form by giving by 4th table}

= 21 : 22

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Plz hurry!!!! thank you!!!!

Nikitich [7]

Answer:

Area of trapezium = 4.4132 R²

Step-by-step explanation:

Given, MNPK is a trapezoid

MN = PK and ∠NMK = 65°

OT = R.

⇒ ∠PKM = 65° and also ∠MNP = ∠KPN = x (say).

Now, sum of interior angles in a quadrilateral of 4 sides = 360°.

⇒ x + x + 65° + 65° = 360°

⇒ x = 115°.

Here, NS is a tangent to the circle and ∠NSO = 90°

consider triangle NOS;

line joining O and N bisects the angle ∠MNP

⇒ ∠ONS = $\frac{115}{2}$ = 57.5°

Now, tan(57.5°) = $\frac{OS}{SN}$

⇒ 1.5697 = $\frac{R}{SN}$

⇒ SN = 0.637 R

⇒ NP = 2×SN = 2× 0.637 R = 1.274 R

Now, draw a line parallel to ST from N to line MK

let the intersection point be Q.

⇒ NQ = 2R

Consider triangle NQM,

tan(∠NMQ) = $\frac{NQ}{QM}$

⇒ tan65° = $\frac{NQ}{QM}$

⇒ QM = $\frac{2R}{2.1445}$

QM = 0.9326 R .

⇒ MT = MQ + QT

= 0.9326 R + 0.637 R (as QT = SN)

⇒ MT = 1.5696 R

⇒ MK = 2×MT = 2×1.5696 R = 3.1392 R

Now, area of trapezium is (sum of parallel sides/ 2)×(distance between them).

⇒ A = ( $\frac{NP + MK}{2}$ ) × (ST)

= ( $\frac{1.274 R + 3.1392 R}{2}$ ) × 2 R

= 4.4132 R²

⇒ Area of trapezium = 4.4132 R²

5 0

3 years ago

Find sin(a)&cos(B), tan(a)&cot(B), and sec(a)&csc(B).

Reil [10]

Answer:

Part A) $sin(\alpha)=\frac{4}{7},\ cos(\beta)=\frac{4}{7}$

Part B) $tan(\alpha)=\frac{4}{\sqrt{33}},\ tan(\beta)=\frac{4}{\sqrt{33}}$

Part C) $sec(\alpha)=\frac{7}{\sqrt{33}},\ csc(\beta)=\frac{7}{\sqrt{33}}$

Step-by-step explanation:

Part A) Find $sin(\alpha)\ and\ cos(\beta)$

we know that

If two angles are complementary, then the value of sine of one angle is equal to the cosine of the other angle

In this problem

$\alpha+\beta=90^o$ ---> by complementary angles

so

$sin(\alpha)=cos(\beta)$

Find the value of $sin(\alpha)$ in the right triangle of the figure

$sin(\alpha)=\frac{8}{14}$ ---> opposite side divided by the hypotenuse

simplify

$sin(\alpha)=\frac{4}{7}$

therefore

$sin(\alpha)=\frac{4}{7}$

$cos(\beta)=\frac{4}{7}$

Part B) Find $tan(\alpha)\ and\ cot(\beta)$

we know that

If two angles are complementary, then the value of tangent of one angle is equal to the cotangent of the other angle

In this problem

$\alpha+\beta=90^o$ ---> by complementary angles

so

$tan(\alpha)=cot(\beta)$

<em>Find the value of the length side adjacent to the angle alpha</em>

Applying the Pythagorean Theorem

Let

x ----> length side adjacent to angle alpha

$14^2=x^2+8^2\\x^2=14^2-8^2\\x^2=132$

$x=\sqrt{132}\ units$

simplify

$x=2\sqrt{33}\ units$

Find the value of $tan(\alpha)$ in the right triangle of the figure

$tan(\alpha)=\frac{8}{2\sqrt{33}}$ ---> opposite side divided by the adjacent side angle alpha

simplify

$tan(\alpha)=\frac{4}{\sqrt{33}}$

therefore

$tan(\alpha)=\frac{4}{\sqrt{33}}$

$tan(\beta)=\frac{4}{\sqrt{33}}$

Part C) Find $sec(\alpha)\ and\ csc(\beta)$

we know that

If two angles are complementary, then the value of secant of one angle is equal to the cosecant of the other angle

In this problem

$\alpha+\beta=90^o$ ---> by complementary angles

so

$sec(\alpha)=csc(\beta)$

Find the value of $sec(\alpha)$ in the right triangle of the figure

$sec(\alpha)=\frac{1}{cos(\alpha)}$

Find the value of $cos(\alpha)$

$cos(\alpha)=\frac{2\sqrt{33}}{14}$ ---> adjacent side divided by the hypotenuse

simplify

$cos(\alpha)=\frac{\sqrt{33}}{7}$

therefore

$sec(\alpha)=\frac{7}{\sqrt{33}}$

$csc(\beta)=\frac{7}{\sqrt{33}}$

6 0

3 years ago

12. 13. 15. Plz help

Lera25 [3.4K]

12. 37, 370, 10^2
13. 20.4, 10^2, 2040
15. 1000*1.75=1750
Hope it helped!

6 0

3 years ago

Read 2 more answers

The amount of time it takes a swimmer to swim a race is inversely proportional to the average speed of the swimmer. A swimmer fi

Ket [755]

9514 1404 393

Answer:

3 feet per second

Step-by-step explanation:

If the time is multiplied by 2, the inverse relationship tells you the speed is multiplied by 1/2.

(1/2)(6 ft/s) = 3 ft/s

The swimmer's average speed is 3 ft/s.

4 0

3 years ago

Find the distance between two points C(-6,5) and D(-3,1)

gladu [14]

The formula of a distance between two points:

$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

We have:

$C(-6,\ 5)\to x_1=-6,\ y_1=5\\D(-3,\ 1)\to x_2=-3,\ y_2=1$

substitute:

$d=\sqrt{(-3-(-6))^2+(1-5)^2}=\sqrt{3^2+(-4)^2}=\sqrt{9+16}=\sqrt{25}=5$

Answer: 5 units.

6 0

3 years ago