A bus travels 300 kilometers at a given speed. If the speed is increased by 5 kilometers per hour, the trip will be reduced by two hours. Find the speed.

25km/hr (take the word train as bus )

Step-by-step explanation:

Answer

Let x km/hr be the constant speed of the train,

Then Time taken to cover 300km=

x

300

hrs

Time taken to cover 300km when the speed is increased by 5km/hr=

x+5

300

hours

It is given that the time to cover 300km is reduced by 2 hours

∴

x

300

−

x+5

300

=2

⇒

x(x+5)

300(x+5)−300x

=2⇒2x

2

+10x=1500

⇒x

2

+5x−750=0⇒x

2

+30x−25x−750=0

⇒(x+30)(x−25)=0⇒x=25orx=−30

But x cannot be negative. Therefore x=25

Hence, the original speed of the train is 25km/hr

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.

the value of x is 9 ⇒ answer b

step-by-step explanation:

* we can solve this problem using cosine and sine rule

- in δ abc

∵ ab = 36 , bc = 28 , ac = 16

- lets find the measure of angle b using the cosine rule

∵ cos b = [ab² + bc² - ac²]/2(ab)(bc)

∴ cos b = [36² + 28² - 16²]/2(36)(28)

∴ cos b = 19/21

∴ m∠b = cos^-1(19/21) ≅ 25°

- lets find the measure of angle a using the sine rule

∵ sina/bc = sinb/ac = sinc/ab

∴ sina/28 = sin25°/16 ⇒ by using cross multiplication

∴ sina = 28 × sin25°/16

∴ sina = 0.7396

∴ m∠a = sin^-1(0.7396) ≅ 48°

- from the figure m∠abd = m∠dbc

∵ m∠abc = 25°

∴ m∠abd = 25°/2 = 12.5°

- in δabd

∵ m∠a = 48° , m∠abd = 12.5°

∵ the sum of the measures of the interior angles of any δ is 180°

∴ m∠adb = 180° - (48° + 12.5°) = 119.5°

∵ ab = 36

∵ ad = x

- use the sine rule to find x

∵ sin∠adb/ab = sin∠abd/x

∴ sin119.5°/36 = sin12.5°/x ⇒ by using cross multiplication

∴ x = 36 × sin12.5°/sin119.5° = 8.95 ≅ 9

* the value of x is 9