Question

car making a 100km journey Travels 40kmph for the first 50 km how fast must go during the second 50km to attain a average 50 km per hour?? ​

Answer 1

Heyy Mate here To This Attachment....

Answer 2

Heya mate......

here is your ans

$average \: speed \: = \frac{total \: distance travelle}{total \: time \: taken}$

$average \: speed \: = \frac{d1 + d2}{ \frac{d1}{s1} + \frac{d2}{s2} }$

But d1 = d2 therefore

let it be simply d

$average \: speed \: = \frac{2d}{d( \frac{1}{s1} + \frac{1}{s2} )}$

$average \: speed \: = \frac{s1 \times s2}{(s1 + \: s2)}$

Given..

• speed1 = 40 km/h
• speed 2 = ?
• average speed = 50 km/h

putting all in the formula

$50 = 2 \times (\frac{40 \times s2}{40 + s2} )$

$25 \times (40 + s2) = 40 \times s2$

$1000 + 25s2 = 40s2$

$1000 = 15s2$

$s2 = \frac{1000}{15}$

$s2 = \frac{200}{3} kmph$

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#MissNostalgia