SOLUTION: Two brothers start at same time from two places 20 kms apart. If they walk in same
direction, elder brother overtakes the younger in 10 hrs, but if they walk in opposite
directio
Algebra.Com
Question 879989: Two brothers start at same time from two places 20 kms apart. If they walk in same
direction, elder brother overtakes the younger in 10 hrs, but if they walk in opposite
directions, they meet in 2 hrs. Find the rates at which they walk.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let the rate of the elder brother =
Let the rate of the younger brother =
-----------------
The elder brother has to have the faster rate
in order to catch up with the younger brother
----------------------------------------
Also, when they walk in opposite directions,
they must be walking towards each other, or
else they would never meet
----------------------------
Let = distance the elder brother has
to travel to catch younger brother
Walking in same direction:
Equation for younger brother:
(1)
Equation for elder brother:
(2)
==============
Walking towards each other:
Think of this as the elder brother moving
at the sum of their speeds and the
younger brother not moving
(3)
------------------------
Substitute (2) into (1)
(1)
(1)
(1)
and
(3)
--------------------------
Add (1) and (3)
and, since
(3)
(3)
(3)
---------------
The eldest brother's rate is 6 km/hr
The younger brother's rate is 4 km/hr
---------------
check:
(2)
(2) km
and
(1)
(1)
(1) km
OK
RELATED QUESTIONS
Two persons A and B start at the same time from two palces 20km apart. If they walk in... (answered by venugopalramana)
two person 27 kilometers apart start at the same time are together in 9 hours if they... (answered by ankor@dixie-net.com)
at the beginning of a walk roberto and juanita are 7.7 miles apart. if they leave at the... (answered by robertb)
TWO PERSONS 27 KM APART STARTING AT THE SAME TIME ARE TOGETHER IN 9 HOURS IF THEY WALK... (answered by ankor@dixie-net.com)
Two men start from two places 50 km apart.when they travel in opposite directions,they... (answered by lwsshak3)
Two people, 27 km apart, setting out at the same time are together in 9 hours if they... (answered by jorel555)
Two persons 27 km apart starting at the same time are together in 9 hours if they walk in (answered by robertb)
two racers 15 miles apart start at the same time traveling in the same direction. after 6 (answered by richwmiller)
At the beginning of the walk, robert and juan are 5.5 miles apart. If they leave at the... (answered by mananth)