Difficult Distance, Speed and time problems

• Dec 21st 2009, 06:50 AM
saberteeth
Difficult Distance, Speed and time problems
1) A man takes 5 hrs and 45 mins to walk to a certain place and ride back. He would have gained 2 km by riding both ways. The time he would take to walk both ways is?

2) A jeep travels a distance of 100 km at a uniform speed. If the speed of the jeep is 5km/hr, then it takes 3 hrs to cover the same distance. Find the original speed of the jeep.

3) A train overtakes two men walking in the same direction as the train at the speed of 3km/hr and 4.5km/he in 8 and 12 sec respectively. Find the length of the train.
• Dec 22nd 2009, 03:52 AM
mr fantastic
Quote:

Originally Posted by saberteeth
1) A man takes 5 hrs and 45 mins to walk to a certain place and ride back. He would have gained 2 km by riding both ways. The time he would take to walk both ways is?

[snip]

$\frac{d}{v_1} + \frac{d}{v_2} = \frac{23}{4}$ .... (1)

$\frac{2d}{v_2} = \frac{15}{4}$ .... (2) (assuming that when you typed 'gained 2 km' you meant 'gained 2 hours').

Substitute equation (2) into equation (1) and solve for $\frac{2d}{v_1}$.