Question

In a flight of 2800 km' an aircraft was slowed down due to bad weather. Its average speed is reduced by 100 km/tr and time increasto uy io minutes. Find the o.igirur duration of the flight.​

Answer 1

GIVEN:-

GIVEN:-D=2800 km,

GIVEN:-D=2800 km,Now,

$t = \frac{2800}{speed}$

$= > speed = \frac{2800}{t}$

ACCORDING TO QUESTION:

$t2 = t + ( \frac{1}{60} hr)$

$t2 = \frac{61t + 1}{60}$

Then,

$\frac{2800}{t} - \frac{2800}{t2} = 100$

but t2=t+1,

$\frac{2800}{t} - \frac{2800}{ \frac{61 t + 1}{60} } = 100$

cross multiple:

$\frac{2800}{t} - \frac{168000}{61t + 1} = 100$

$\frac{170,800t + 2800 - 168000t}{61t {}^{2} + t} = 100$

$2800t + 2800 = 6100t {}^{2} + 100t$

$= > 2800 = 6100t {}^{2} - 2700t$

$= >6100t {}^{2} - 2700t - 2800 = 0$

Divide each by 100:

$= > 61t {}^{2} - 27 t - 28 = 0$