Question

A man cycles from A to B, a distance of 20 km in 1 hour and 20 minutes. The road from A is at level for 12 km and then it is uphill to B. If the man's average speed on level is 18 km/hr, then what is his uphill speed.
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Answer 1

Answer:

Let the original average speed of the cyclist be x km/hr

Time=

Speed

Distance

Then as per given condition

(x−1)

14

=

x

14

+

3

1

⇒

x(x−1)

14x−14(x−1)

=

3

1

⇒

x

2

−x

14

=

3

1

⇒x

2

−x−42=0

⇒x

2

−7x+6x−42=0

⇒x(x−7)+6(x−7)=0

⇒(x−7)(x+6)=0

⇒x=7 or −6