Walking at 7/9 of his usual speed, an accountant is 20 minutes late to his branch. What is his usual time to reach the destination? MCQ with Answer and Explanation
Walking at 7/9 of his usual speed, an accountant is 20 minutes late to his branch. What is his usual time to reach the destination?
A. 70 minutes
B. 90 minutes
C. 80 minutes
D. 60 minutes
Answer: Option A
Solution (By JKSSB Mock Tests)
New speed = 7/9 of usual speed => New time = 9/7 of usual time. Difference = 2/7 of usual time = 20 minutes. Therefore, 1/7 of usual time = 10 minutes => Usual time = 70 minutes.
A regular passenger bus tracks a route divided into three equal segments. It runs the segments at 20 km/h, 30 km/h, and 60 km/h respectively. Find the average speed across the whole route.
Explanation:
Let each segment distance be 60 km. Total distance = 3 * 60 = 180 km. Total time = 60/20 + 60/30 + 60/60 = 3 + 2 + 1 = 6 hours. Average speed = 180 / 6 = 30 km/h.
A car covers a distance from town X to town Y at a speed of 45 km/h and returns at a speed of 75 km/h. If the total journey takes 8 hours, find the one-way distance between the two towns.
Explanation:
Let the one-way distance be d km. Time taken forward = d/45 and return = d/75. Given: d/45 + d/75 = 8. (5d + 3d) / 225 = 8 => 8d / 225 = 8 => d = 225 km.
Explanation:
Upstream speed = 24 / 4 = 6 km/h. Upstream Speed = Speed in still water - Current speed => 6 = Speed in still water - 2 => Speed in still water = 8 km/h.
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