Answers

2015-11-15T15:17:43+05:30
Let the earlier speed be X km / hr

Increased speed = (X + 250) km / hr

1500 / X - 1500 / ( X +250) = 1/2

MULTIPLY BY 2X*( X +250)

3000 ( X +250) - 3000X = X( X +250)

3000X + 750000 - 3000X = X^2 + 250X

X^2 + 250X - 750,000 = 0

X^2 +1000X -750X - 750,000 = 0

X ( X + 1000) -750 ( X + 1000) = 0

( X - 750) ( X + 1000) = 0

X = 750

X + 250 = 1000 km / hr ANSWER
CHECK
1500/1000 = 1.5 hours
1500/750 = 2 hours
2 - 1.5 = 1/2 hour
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