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Q.)An aeroplane flies with an average speed of 756 km/h. A helicopter takes 48 h to cover twice the distance covered by aeroplane in 9 h. How much distance will the helicopter cover in 18 h? (Assuming that flights are non-stop and moving with uniform speed.)

(a) 5010 km

(b) 4875 km

(c) 5760 km

(d) 5103 km

[SNAP Question, SNAP 2013 Question, Time and Distance, Uniform SPeed]

Solution :

A helicopter takes 48 h to cover twice the distance covered by aeroplane in 9 h.

=> 2*Distance covered by aeroplane in 9 hours = Distance covered by helicopter in 48 hours = X km (Suppose)

Distance covered by aeroplane in 1 hour = $\frac{X}{2*9}$ = $\frac{X}{18}$ km

Hence, Speed of aeroplane = $\frac{X}{18}$ km/h

=> 756 = $\frac{X}{18}$ km/h

=> X = 756*18 kms

Distance covered by helicopter in 1 hour = $\frac{X}{48}$ = $\frac{X}{48}$ = $\frac{756*18}{48}$

Hence , Distance covered by helicopter in 18 hour = $\frac{756*18*18}{48}$ = 5103 km

Hence, OPTION(d)