Multiply km/hr by what to obtain m/s?
A. 18/5
B. 5/18
C. 3600
D. 1000

Ans: B
Explanation: Multiply by 5/18 because 1 km = 1000 m and 1 hr = 3600 s; simplifies to 5/18.

Fill in the blank: Speed = ___ / Time

Distance

True/False: Relative speed equals sum of speeds when directions opposite.

True

Why total distance at nth meeting equals (2n-1)·d?

Each meeting adds odd multiples
Alternate full round-trip contributions
Total becomes (2n-1)·d

Average speed for equal distances at speeds x and y?
A. (x+y)/2
B. 2xy/(x+y)
C. √(xy)
D. (x+y)/x

Ans: B
Explanation: Equal distances weight times inversely by speeds; harmonic mean 2xy/(x+y) gives overall average speed.

True/False: When a train passes a platform, distance equals train length.

False: Distance equals train length plus platform length; platform is non-point and adds to covered distance.

Formula for downstream and upstream speeds?

Downstream = u + v
Upstream = u - v

Relative speed for same direction speeds X and Y?
A. X + Y
B. X - Y
C. |X + Y|
D. XY

Ans: B
Explanation: Same direction relative speed equals difference of speeds because one body overtakes the other.

Which equals 1 mile in kilometers?
A. 1.609 km
B. 1.6 km
C. 2 km
D. 0.621 km

Ans: A
Explanation: 1 mile equals 1.609 kilometers; use this conversion when changing distance units accurately.

Time to cross opposite-direction trains lengths L1 and L2 speeds X and Y?
A. (L1+L2)/(X+Y)
B. (L1+L2)/(X-Y)
C. |L1-L2|/(X+Y)
D. (L1×L2)/(X+Y)

Ans: A
Explanation: Opposite directions add velocities; distance to cover is L1+L2, so time = (L1+L2)/(X+Y).

True/False: Same-direction relative speed equals X+Y.

False: Same-direction relative speed equals difference of speeds (X-Y); sum applies only for opposite directions.

Total distance at nth meeting equals?
A. (2n-1)·d
B. n·d
C. 2n·d
D. (n-1)·d

Ans: A
Explanation: Meeting intervals produce odd multiples of separation; nth meeting totals (2n-1)·d by pattern derivation.

If speed ratio is p:q, what is time ratio for same distance?

Time ratio = q:p
Because time ∝ 1/speed

Upstream speed equals which expression?
A. u + v
B. u - v
C. v - u
D. u×v

Ans: B
Explanation: Upstream opposes the stream, reducing effective speed to boat speed minus stream speed, u-v.

True/False: Average speed equals total distance divided by total time.

True