Question

A person takes 20 minutes more to cover a certain distance by decreasing his speed by 20%. What is the time taken to cover the distance at his original speed ?
A) 1hr
B) 1 hr 20 min
C) 1 hr 10 min
D) 50 min

Answer 1

Hey mate ^_^

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Answer:
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Let the distance and original speed be 'x' km and 'y' kmph respectively.

$\frac{x}{0.8k} = \frac{20}{60}$

$\frac{5x}{4y} = \frac{1}{3}$

$\frac{5x - 4x}{4y} = \frac{1}{3}$

$x = \frac{4}{3y}$

Time taken to cover the distance at original speed

$= \frac{x}{y}$

$= \frac{4}{3}$

$= 1 \: hr \: 20 \: min$

Therefore,

Correct option B) 1 hr 20 min

#Be Brainly❤️

Answer 2

Answer:

Option(B)

Step-by-step explanation:

Here, he is decreasing his speed by 20% = 0.8.

According to the given condition.

d/0.8s - d/s = 20 minutes

d/0.8s - d/s = 20/60

10d/8s - d/s = 1/3

5d/4s - d/s = 1/3

(5d - d)/4s = 1/3

d/4s = 1/3

d/s = 4/3

d/s = (1 + 1/3) hour

d/s = 1 hour + (1/3) hour

d/s = 1 hour + (20/60) hour

d/s = 1 hour + 20 minutes.

Hope it helps you.

#Bebrainly