M and n are 2 points on a straight road Yamuna and Ganga run from m an...
Problem Analysis:
We are given that two points M and N are on a straight road. Yamuna and Ganga start from M and N respectively and move towards each other. After crossing each other, they reach their respective destinations in 2 minutes and 8 minutes respectively. We need to find the ratio of Yamuna's speed to Ganga's speed.
Let's assume:
Let the distance between M and N be D units.
Let the speed of Yamuna be x units/minute.
Let the speed of Ganga be y units/minute.
Calculating the distances:
When Yamuna and Ganga start from their respective points and move towards each other, they will meet at some point P on the road. Let the distance between M and P be d units. Therefore, the distance between P and N will be (D - d) units.
Since Yamuna and Ganga reach their respective destinations in 2 minutes and 8 minutes respectively, we can write the equation:
d/x + (D - d)/y = 2 (Equation 1)
(D - d)/x + d/y = 8 (Equation 2)
Simplifying Equation 1, we get:
d/y + (D - d)/y = 2x
(D - d)/y = 2x - d/y
Substituting this value in Equation 2, we get:
(D - d)/x + 2x - d/y = 8
Simplifying further, we get:
(D - d)/x + d/y = 8 - 2x
We can further simplify this equation as:
D/x - d/x + d/y = 8 - 2x
D/x + d/y = 8 - 2x + d/x
Solving the equations:
From Equation 1, we have:
d/x + (D - d)/y = 2
Multiplying both sides by xy, we get:
yd + x(D - d) = 2xy
Expanding and rearranging, we get:
yd + xD - xd = 2xy
yd - xd = 2xy - xD
d(y - x) = x(2y - D)
d = x(2y - D)/(y - x)
Substituting this value of d in the equation D/x + d/y = 8 - 2x + d/x, we get:
D/x + x(2y - D)/(y - x)y = 8 - 2x + x(2y - D)/x
Simplifying, we get:
D/x + 2y - D/y = 8 - 2x + 2y - D/x
Further simplifying, we get:
D/x - D/y = 8 - 2x - D/x
D/x - D/y - D/x = 8 - 2x
-D/y = 8 - 2x
D/y = 2x - 8
D/y = 2(x - 4)
Conclusion:
From the above equation, we can see that the ratio of D/y to x - 4 is 2. Therefore, the ratio of Yamuna's speed to Ganga's speed is 2.
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