Question

A person travels a total distance in t)
avels a total distance in three parts in the
ratio 4: 3:1 with a constant speed of 90 km h 1
20 m-1 and 10 ms, respectively. What is the average
speed of the person while journey?​

Answer 1

Answer:

avg speed = total distance

total time

total distance = 4t ×90 + 3t × 20 +t × 10

8. 8 8

= 430t

8

time = t

avg speed = 430t = 53.75m/s

8

Answer 2

Given that,

A person travels a total distance in travels a total distance in three parts in the  ratio 4: 3:1 with a constant speed of 90 km/h 20 m/s and 10 m/s

To find,

Average speed of the person.

Solution.

Let the person covers total distance of x.

For first part,

$d_1=\dfrac{4x}{8}=\dfrac{x}{2}$

Time,

$t_1=\dfrac{d_1}{v_1}\\\\t_1=\dfrac{x}{2\times 25}\\\\t_1=\dfrac{x}{50}\ .......(1)$

For second part,

$d_2=\dfrac{3x}{8}=\dfrac{3x}{8}$

Time,

$t_2=\dfrac{d_2}{v_2}\\\\t_2=\dfrac{3x}{8\times 20}\\\\t_2=\dfrac{3x}{160}\ .......(2)$

For third part,

$d_3=\dfrac{x}{8}$

Time,

$t_3=\dfrac{d_3}{v_3}\\\\t_3=\dfrac{x}{8\times 10}\\\\t_3=\dfrac{x}{80}\ .......(3)$

Average speed of the person is given by :

$v=\dfrac{\text{total distance}}{\text{total time}}\\\\v=\dfrac{x}{t_1+t_2+t_3}\\\\v=\dfrac{x}{(x/50)+(3x/160)+(x/80)}$

$v=19.51\ m/s$

So, the average speed of the person is 19.51 m/s.

Learn more,

Average speed

https://brainly.in/question/11308038