Two cars start at the same time from in point and move alone two roads, at right angle to each other. The speeds are 36 km/hr and 48 km/hr respectively. After 15 sec distance between them will be :
A. 400 m
B. 150 m
C. 300 m
D. 250 m
Answer: Option D
Solution(By Examveda Team)
Distance travelled by the 1st car in 15 seconds
$$\eqalign{ & {\text{OA}} = \left( {36 \times \frac{5}{{18}}} \right) \times 15\,{\text{m}} \cr & \,\,\,\,\,\,\,\,\,\,\, = 150\,{\text{m}} \cr} $$
Distance travelled by the 2nd car in 15 seconds
$$\eqalign{ & {\text{OB}} = \left( {48 \times \frac{5}{{18}}} \right) \times 15\,{\text{m}} \cr & \,\,\,\,\,\,\,\,\,\, = 200\,{\text{m}} \cr} $$
∴ Distance between them after 15 seconds
$$\eqalign{ & {\text{AB}} = \sqrt {{\text{O}}{{\text{A}}^2} + {\text{O}}{{\text{B}}^2}} \cr & \,\,\,\,\,\,\,\,\,\, = \sqrt {{{150}^2} + {{200}^2}} \cr & \,\,\,\,\,\,\,\,\,\, = \sqrt {22500 + 40000} \cr & \,\,\,\,\,\,\,\,\,\, = \sqrt {62500} \cr & \,\,\,\,\,\,\,\,\,\, = 250\,{\text{m}} \cr} $$
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Comments ( 1 )
Related Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
good answer and easy to understand