Rohit and Dinesh are 64 km apart. Rohit can walk at a speed of 15 km/hr and Dinesh at the speed of 17 km/hr. In how many hours will they meet if they are travelling towards each other?
2 hours
This problem involves calculating the time it takes for two individuals, Rohit and Dinesh, to meet when travelling towards each other.
When two objects move towards each other, their speeds add up. This is called their relative speed. The formula for relative speed ($v_{rel}$) is:
$v_{rel} = v_R + v_D$
Add the speeds of Rohit and Dinesh:
$v_{rel} = 15 \text{ km/hr} + 17 \text{ km/hr} = 32 \text{ km/hr}$
The time ($t$) it takes for them to meet can be calculated using the formula:
$t = \frac{\text{Distance}}{\text{Relative Speed}} = \frac{d}{v_{rel}}$
Substitute the values:
$t = \frac{64 \text{ km}}{32 \text{ km/hr}}$
$t = 2 \text{ hours}$
Therefore, Rohit and Dinesh will meet in 2 hours.
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