Question

A man can cover a distance in 1hr 24min by covering 2/3 of the distance at 4 km/h and the rest at 5km/h. The total distance is

A. 5km

B. 6km

C. 7km

D. 8km

Answer 1

Answer:

Step-by-step explanation:

Disctance travelled in 4 km/hr =  \frac{2}{3}  D

Distance travelled in 5 km/hr =  \frac{1}{3}  

So,  

 \frac{2D}{3*4}  +  \frac{D}{3*5}  

=  \frac{84}{60}  

D = 6 km

Answer 2

The correct option is, (B) 6km.

What is distance in physics terms?

• Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion.
• Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.

According to the question:

Let the total distance is x km.

Total time=1 hr 24 min= $\frac{21}{15}$  min

Tarun covers $\frac{2}{3}$ of the distance at 4 km/hr then time to cover this distance = $\frac{2/3s}{4}$

Remaining distance = $s-\frac{2}{3 s}=\frac{1}{3 s}$

Tarun covers rest of the distance at 5 km/hr then time to cover rest distance = $\frac{\frac{1}{3 s}}{5}$

$\frac{21}{15}=\frac{2}{12 \mathrm{~s}}+\frac{1}{15 \mathrm{~s}}\\ \Rightarrow \frac{21}{15}=\frac{14}{60 \mathrm{~s}}\\ \mathrm{~s}=\frac{14 \times 15}{21 \times 60}\\\\=6 \mathrm{~km}$

Hence, total distance are 6km.

Learn more about distance here,

​https://brainly.in/question/7737285?msp_poc_exp=5

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