SOLUTION: Two men A and B walk from P to Q a distance of 'D' at S1 and S2 km per hour. B reaches Q,returns immediately and meets A at R,find the distance from P to Q. I need an explanation

Question 879100: Two men A and B walk from P to Q a distance of 'D' at S1 and S2 km per hour. B reaches Q,returns immediately and meets A at R,find the distance from P to Q. I need an explanation for this rather than mere formula. thank you in advance.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Two men A and B walk from P to Q a distance of 'D' at S1 and S2 km per hour. B reaches Q,returns immediately and meets A at R,find the distance from P to Q.
:
When they meet:
A: travels (D-R)
B: travels (D+R)
:
Their travel time is the same; write a time equation: time = dist/speed
=
Cross multiply
S2(D-R) = S1(D+R)
S2D - S2R = S1D + S1R
S2D - S1D = S1R + S2R
Factor out D & R
D(S2-S1) = R(S1+S2)
D = is the distance from P to Q
RELATED QUESTIONS
A student starting from his house walk at a speed of 2.5 km per hour and reaches his... (answered by josgarithmetic,MathTherapy)

A man goes at the speed of 5 km/hour from P to Q and returns at the speed of 3 km/hour... (answered by ankor@dixie-net.com)

A train (a) travels from p to q at a rate of 24.5 km/h. After it has been gone 1.4... (answered by richwmiller)

Town P and Q are 265 km apart. Car A started from P at 60 km/hr at 8.00 am towards Q. Car (answered by ankor@dixie-net.com)

Two trains P and Q are traveling from station A to station B at speeds of 100kmph and 120 (answered by ankor@dixie-net.com)

Two places P and Q are 324 kilometers apart. A man leaves P for Q and at the same time... (answered by josgarithmetic)

If a man travels p hours at an average rate of q miles per hour and then r hours at an... (answered by ikleyn)

A sample is selected from one of two populations, S1 and S2, with P(S1) = 0.7 and (answered by Theo,ikleyn,Edwin McCravy,math_tutor2020)

I have sent this before and I've checked the solutions on the website on this topic but I (answered by venugopalramana)