Average Speed - Set 10 - Try Out - Quantitative Knowledge - SNBT

Nina runs at a constant speed of $5 \text{ km/h}$ . And she walks at a speed of $1 \text{ km/h}$ . If Nina travels $3 \text{ km}$ by running for half of the total travel time and walking for the rest, what is the total time taken by Nina?

Explanation

We know that:

\text{speed} \times \text{time} = \text{distance}

Then:

	Speed	Time	Distance
Run	$5 \text{ km/h}$	$x \text{ hours}$	$5x \text{ km}$
Walk	$1 \text{ km/h}$	$x \text{ hours}$	$x \text{ km}$

Nina travels a distance of $3 \text{ km}$ .

\text{running} + \text{walking} = 3 \text{ km}

5x \text{ km/h} + x \text{ km/h} = 3 \text{ km}

6x \frac{\text{km}}{\text{h}} = 3 \text{ km}

x = \frac{1}{2} \text{ hour}

The total time taken by Nina is the sum of the time spent running and walking, which is:

\text{Total time} = x + x = 2x

\text{Total time} = 2 \left(\frac{1}{2}\right) = 1 \text{ hour}

Convert to minutes:

1 \text{ hour} = 60 \text{ minutes}

Thus, the total time taken by Nina is $60$ minutes.

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Number 10

Explanation