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Points 'A' and 'B' are 70 km apart on a highway and two cars start at the same time. If they travel in the same direction, they meet in 7 hours, but if they travel towards each other they meet in one hour. Find the speed of the two cars (in km/hr).
Answer & Solution
Correct Answer:
Option
B
Let the speed of the cars be S1 and S2
And S1 - S2 = $$\frac{70}{7}$$ = 10 . . . . . (i)
Also S1 + S2 = $$\frac{70}{1}$$ = 70 . . . . . (ii)
From equation (i) and (ii)
S1 = $$\frac{10 + 70}{2}$$ = 40 km /hr
And S2 = $$\frac{70 - 10}{2}$$ = 30 km / hr
∴ Required speeds are 40 km/hr and 30 km/hr
And S1 - S2 = $$\frac{70}{7}$$ = 10 . . . . . (i)
Also S1 + S2 = $$\frac{70}{1}$$ = 70 . . . . . (ii)
From equation (i) and (ii)
S1 = $$\frac{10 + 70}{2}$$ = 40 km /hr
And S2 = $$\frac{70 - 10}{2}$$ = 30 km / hr
∴ Required speeds are 40 km/hr and 30 km/hr
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