A and B started travelling towards each other at the same time, from places X to Y and Y to X, respectively. After crossing each other. A and B took 2.45 hours and 4.05 hours to reach Y and X, respectively. If the speed of B was 8.4 km/h, then what was the speed (in km/h) of A?
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3:5
Step-by-step explanation:
Let say Distance between A & B is D km
Speed of Train starting from A = A km/Hr
Speed of Train Starting from B = B km/Hr
Let say after T hr they crossed each other
=> AT + BT = D - eq 1
=> T = D/(A+B)
A ( T + 25) = D => AT + 25A = D - eq2
B ( T + 9) = D => BT + 9B = D - eq 3
Eq 2 + eq3 - eq 1
=> 25A + 9B = D
=> 25A + 9B = AT + BT - eq 4
Eq 2 - E3
AT - BT + 25A - 9B = 0
=> 25A - 9B = BT - AT - eq 5
Adding eq 4 & eq 5
50A = 2BT
=> 25A = BT - eq 6
Eq 4 - Eq 5
18B = 2AT
=> 9B = AT - eq 7
eq6/eq7
25A/9B = BT/AT
=> 25A/9B = B/A
=> 25A² = 9B²
=> A²/B² = 9/25
=> A/B = 3/5
A: B :: 3: 5
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