Question

Unitary Method
A bus can cover a distance of 240 km in 4 hours.
i find the speed of the bus in km per hour.
ii How many kilometers does it cover with the same speed in 12 hours.

Answer 1

Answer:

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Step-by-step explanation:

Uniform speed =x km/h

distance =240 km

time =SpeedDistance

=x240hours

Due to heavy rain speed =(x−10) km/h

Now time =x−10240 hours

According to question

x−10240−x240=2

x(x−10)240x−240(x−10)=2

x2−10x240x−240x+2400=2

⇒2x2−20x−2400=0

⇒x2−10x−1200=0

x2−40x+30x−1200=0

x(x−40)+30(x−40)=0

⇒(x−40)(x+30)=0

x=40 and x=−30 (speed can not be negative)

∴ uniform speed =40