Data sufficiency question: What are the speeds two trains travels with 80 yards and 85 yards long respectively? (Assume that former is faster than later)a) they take 75 seconds to pass each other in opposite direction.b) they take 37.5 seconds to pass each other in same direction

Data sufficiency question: What are the speeds two trains travels with 80 yards and 85 yards long respectively? (Assume that former is faster than later)

a) they take 75 seconds to pass each other in opposite direction.

b) they take 37.5 seconds to pass each other in same direction

2.225 yards/sec and 1.235 yards/sec

1.165 yards/sec and 1.035 yards/sec

2.325 yards/sec and 1.525 yards/sec

1.125 yards/sec and 1.425 yards/sec

Explanation:

Let the speeds be x and y

When moves in same direction the relative speed,

x - y = (85-80)37.5(85-80)37.5 = 0.13 - - - - - (I)

When moves in opposite direction the relative speed, x + y = 165/75 = 2.2 - - - - (II)

Now, equation I + equation II gives, 2x = 0.13 + 2.2 = 2.33 => x = 1.165

From equation l, x - y = 0.13 => y = 1.165 - 0.13 = 1.035

Therefore the speeds are 1.165 yards/sec and 1.035 yards/sec.