Elitmus
Exam
Numerical Ability
Arithmetic
Assume that the distance that a car runs on 1 litre of petrol varies inversely as the square of the speed at which it is given. It gives a run of 25 km per litre at a speed of 36 km pH.At wat speed should it be driven to get a run of 36 km per litre?
Read Solution (Total 5)
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- 30 kmph
If the inverse relation of speed & distance or run can be represented with constant'k' then
for Speed=36 kmph,Distance=25 km, So 25=k/(36^2), k=25*36^2
So if speed=x, for distance=36 km then, 36=25*36^2/x^2 or x=30 - 10 years agoHelpfull: Yes(29) No(0)
- d=1/s2
25*36*36=36*x2
x2=25*36*36/36
x=5*36/6
x=30km ph - 10 years agoHelpfull: Yes(4) No(0)
- 5km/hr
X^2=K/Y
K=X^2*Y
for 36km/hr and run of 25km/lt
36=K/25
6^2=K/5^2
K=6^2*5^2
now for the ans:
X=speed=Root over(K/36)=root over(6^2*5^2/6^2)=5*6/6= 5km/hr - 10 years agoHelpfull: Yes(0) No(9)
- speed will be 5km
- 10 years agoHelpfull: Yes(0) No(1)
- its 30km/h.
- 10 years agoHelpfull: Yes(0) No(0)
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