Pakistan MCQs

Downstream speed equals still-water speed plus stream speed.
Thus, 12 + 3 = 15 km/h.

Upstream speed equals still-water speed minus stream speed.
Thus, 10 - 2 = 8 km/h.

Speed equals distance divided by time.
Thus, 180 ÷ 3 = 60 km/h.

Distance equals speed multiplied by time.
Thus, 72 × 2.5 = 180 km.

To convert km/h to m/s, multiply by 5/18.
Thus, 54 × 5/18 = 15 m/s.

To convert m/s to km/h, multiply by 18/5.
Thus, 20 × 18/5 = 72 km/h.

Time equals distance divided by speed.
Thus, 12 ÷ 4 = 3 hours.

For equal distances, average speed is the harmonic mean 2ab/(a + b).
Thus, 2 × 40 × 60 ÷ 100 = 48 km/h.

For equal time intervals, average speed is the arithmetic mean.
Thus, (40 + 60)/2 = 50 km/h.

For opposite directions, relative speeds are added.
Thus, 50 + 70 = 120 km/h.

For motion in the same direction, relative speed is the difference.
Thus, 80 - 55 = 25 km/h.

To pass a pole, the train covers its own length.
Speed = 150 ÷ 10 = 15 m/s.