Time and Distance mixed

 1. Problems on Trains

A train 180 meters long crosses Kinley standing on a platform in 9 seconds. It then crosses a 420-meter-long bridge in 24 seconds. What is the speed of the train in km/h?

Solution:
Let speed = x m/s
Length of train = 180 m
Time to cross bridge = (180 + 420)/x = 24 → 600/x = 24 → x = 25 m/s
Convert to km/h: 25 × 18/5 = 90 km/h

✅ Answer: 90 km/h

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2. Time and Distance

Pema drove from Trongsa to Bumthang at 60 km/h and returned at 40 km/h. What is the average speed for the whole journey?

Solution:
Average speed = 2ab / (a + b) = 2×60×40 / (60+40) = 4800/100 = 48 km/h

✅ Answer: 48 km/h

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3. Height and Distance

From a point 40 m away from the base of the Tashichho Dzong, Sonam observes the top at an angle of 45°. What is the height of the Dzong?

Solution:
tan(45°) = h/40 → 1 = h/40 → h = 40 meters

✅ Answer: 40 meters