plssssss give the ans of these questions and pls don't give useless ans if you know the ans then only give the ans . pls help
Answers
Answer:
1...train must cover 90km in 1hour
2... average speed is 25km/hr
3...and 4... are in pic
Answer 1) Speed of the train in the first 30 km, v1 = 30 km/h Speed of the train in the next 90 km, v2 (to be determined) Average speed = 60 km/h = (v1 + v2)/2 = (30 km/h + v2)/2 ⇒ v2 = 90 km/h
Answer 2) Speed=Distance / time
.°. Time =dist / speed
Let's see the first case,
s = distance = 30 km
v = speed = 40 km/hr
t = time = 30 / 40
=3/4 hrs
Let's see the second case,
s = 30 km
v = 20 km/hr
t = 30 / 20
t = 3/2 hrs
Avg. Speed =Total distance/ Total time
=(30 + 30) / (3/4) + (3/2)
=60 / ( 3 + 6 ) /4
=60 / 9 × 4
=20 / 3 × 4
=80 / 3
=26.67
Answer 3) In the first case, the train travels at a speed of 60 km/h for a time of 0.52 h
Now, Speed = distance / time = 30km/hr
Distance = 60 x 0.52 = 31.2 km --- i)
(ii) In the second case, the train travels at a speed of 30 km/h for a time of 0.24 hr.
Now, speed = distance / time = 30 km/hr
Distance = 30 × 0.24 = 7.2 km --- ii)
(iii) In the third case, the train travels at a speed of 70km/h for a time of 0.71 hr.
Now, speed = distance / time = 70km/hr
Distance = 70 × 0.71 hr .
Now speed = distance / time = 70km/hr
Distance = 70 × 0.71 = 49.7 km ---iii)
From equation 1,2 & 3 we get,
Total distance travelled
= (31.2 + 7.2 + 49.7) km = 88.1 km .
Total time taken = (0.52 + 0.24 + 0.71) hr = 1.47 hr .
Average speed = Total distance travelled / Total time taken
= (88.1/1.47) km /hr
Hence, average speed = 59.9 km/hr
Answer 4) logo
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Question
The train ‘A’ travelled a distance of 120 km in 3 hours whereas another train ‘B’ travelled a distance of 180 km in 4 hours. Which train travelled faster?
Answer
Speed = distance/ time
so speed of A= 120km/3h
A's speed = 40 km/ hr.
Speed of B= 180km/4h
B's speed= 45km/hr.
Hence proved that 'B" moves faster.