A car moves with speed of 30km/h for half an hour; 25 km/h for 1 hour and 40 km/h for 2 hours. find average speed
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Answered by
3
D1 = Speed1 × Time1
==> 30 × 1/2
D1 = 15 Km
D2 = Speed2 × Time2
==> 25 × 1
D2 = 25 Km
D3 = Speed3 × Time3
==> 40 × 2
D3 = 80 Km
Total Distance = D1 + D2 + D3
==> 80 + 25 + 15
==> 105 + 15
==> 120 Km
Total Time = T1 + T2 J+ T3
==> 1/2 + 1 + 2
==> 1 + 2 / 2 + 2
==> 3/2 + 2
==> 7/2
Average Speed = Total Distance / Total Time
==> 120 / 7/2
==> 240 / 7
==> 34.28 Km/h
Answered by
0
Step-by-step explanation:
In case 1:
speed of car =30 km/h
time =30min or 1/2h
distance =30× 1/2=15 km
In case2 :
speed of car = 25 km/h
time =1 h
distance = 25×1= 25 km
In case 3:
speed of car = 40 km/h
time =2 h
distance =40×2 =80 km
From above:
total distance =80+25+15=120 km
total time =3h 30 min
average speed = 120/3.5=80 km/h
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