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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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एका व्यक्तीने 2.5 तास 53 किमी प्रतितास वेगाने गाडी चालवली, नंतर त्याचा वेग 28 किमी प्रतितास वाढवला आणि आणखी एका तासात गंतव्यस्थानावर पोहोचला. संपूर्ण प्रवासात त्या व्यक्तीचा सरासरी वेग (किमी प्रतितास मध्ये) शोधा.
59
58
60
61
61
Calculate distance: (53 × 2.5) + (81 × 1) = 132.5 + 81 = 213.5. Total time = 3.5. Average = 213.5 / 3.5 = 61.
Speed 1 = 53 kmph for Time 1 = 2.5 hours. Speed 2 = 53 + 28 = 81 kmph for Time 2 = 1 hour.
Average Speed=Total TimeTotal Distance=t1+t2d1+d2
Calculate distance: (53 × 2.5) + (81 × 1) = 132.5 + 81 = 213.5. Total time = 3.5. Average = 213.5 / 3.5 = 61.
Many students mistake 'increased his speed by 28' as the new speed (28 kmph) instead of adding it to the original speed (53 + 28 = 81 kmph).
Calculate distance for the first part
Distance d1=Speed×Time=53×2.5.
d1=132.5 km
Calculate speed and distance for the second part
The speed increased by 28 kmph, so new speed is 53+28=81 kmph for 1 hour.
d2=81×1=81 km
Calculate Total Distance and Total Time
Total distance = 132.5+81=213.5 km. Total time = 2.5+1=3.5 hours.
Dtotal=213.5 km,Ttotal=3.5 hours
Final calculation of Average Speed
Divide total distance by total time: 213.5/3.5.
Avg Speed=3.5213.5=61 kmph
D is correct because the average speed calculated using total distance (213.5 km) divided by total time (3.5 hours) is 61 kmph.
This concept is foundational for 'Relative Speed' and 'Trains' problems, where calculating total distance covered at varied speeds is the primary step.