1.

The Distance Of The College And Home Of Rajeev Is 80km. One Day He Was Late By 1 Hour Than The Normal Time To Leave For The College, So He Increased His Speed By 4km/h And Thus He Reached To College At The Normal Time. What Is The Changed (or Increased) Speed Of Rajeev?

Answer»

LET the normal speed be x km/h, then 

80/x-80/(x+4)=1

?x2+4x-320=0

?x (x + 20) - 16 (x + 20) = 0

(x + 20 ) (x - 16) =0

x = 16 km/h

Therefore (x + 4) = 20 km/h

Therefore INCREASED speed = 20 km/h.

Let the normal speed be x km/h, then 

80/x-80/(x+4)=1

?x2+4x-320=0

?x (x + 20) - 16 (x + 20) = 0

(x + 20 ) (x - 16) =0

x = 16 km/h

Therefore (x + 4) = 20 km/h

Therefore increased speed = 20 km/h.



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