Question

A slow jogger runs a mile in 13 min. Calculate speed in. a) in/s b) Km/h

(1mi=1609m); (1in=2.54),

Answer 1

a) 81.23 in per second , b) 7.44 km / hour.

Explanation:

Given: a slow jogger runs a mile in 13 min.

To find: Calculate speed in. a) in/s b) Km/h

Solution : We have given that jogger runs 1 mile = 13 min.

We know that 1 mile = 63360 inches

i minute = 60 second

Then Speed =
`(Distance)/(time)`

Then Speed =
`(1 mile)/(1 minute)`

a ) In inches / second

Plug 1 mile = 63360 inches

13 mint = 780 second

Speed =
`(63360 inches)/(780 second)`

Speed = 81.23 in per second .

b) For km/h

Given 1 mile = 1609 m

1 kilometer = 1000 meter

1 mile = 1.609 km

1 hour = 60 mint

1 mint = 1/60

13 mint =
`(13)/(60)`.

13 mint= 0.216 hour

Then Speed = Speed =
`( 1.609 km)/( 0.216 hour)`

Speed = 7.44 km / hour.

Therefore, a) 81.23 in per second , b) 7.44 km / hour.

Answer 2

The correct answers are A) 7.4 km/hr and B) 81.2 in/s.

Explanation:
A) The original ratio is 1 mi/13 min. We know that 1 mi = 5280 feet, so we have 5280 ft/13 min.
Each foot is 12 inches, so we have 5280*12 = 63360 in
63360 in/13 min

Each minute is 60 seconds; 13*60 = 780
63360 in/780 sec.

Dividing this, we get 81.2 in/sec.

B) 1 mi/13 min; 1 mile = 1609 m, so we have 1609 m/13 min.
1 m = 1000 km, so 1609 m = 1609/1000 = 1.609 km; this gives us 1.609 km/13 min.
An hour is 60 minutes, so we have 1.609 km/(13/60) hr; dividing this, we get 7.4 km/hr.