Question

In a driving competition, Ali and Bilal drove the same course at average speeds of 64 miles per hour and 80 miles per hour, respectively. If it took Ali 50 minutes to drive the course, how long did it take Bilal?

Answer 1

40 minutes.

Explanation:

Bilal's speed is 80/64 = 5/4 times Ali's speed.

So, by proportion, Bilal will take 50 / 5/4 minutes to drive the course.

50 / 5/4

= 50 * 4/5

= 200/5

= 40 minutes.

Answer 2

The time taken by Bilal is: 40 minutes.

Explanation:

It is given that:

Ali and Bilal drove the same distance.

It is given that:

The average speed of Ali is: 64 miles per hour.

The time taken by Ali to drive the course is: 50 minutes.

We know that:

1 hour=60 minutes

i.e.

1 minutes=1/60 hour

i.e.

50 minutes= 5/6 hour

We know that:

`Speed=(Distance)/(Time)`

i.e.

`Distance=Speed* Time`

i.e.

Distance traveled by Ali is:

`Distance=64* (5)/(6)\\\\\\Distance=(160)/(3)\ miles`

Now, the time taken by Bilal is:

`Time=(Distance)/(Speed)\\\\i.e.\\\\Time=((160)/(3))/(80)\\\\i.e.\\\\Time=(160)/(80* 3)\\\\i.e.\\\\Time=(2)/(3)\ hour`

which in minutes is given by:

`=(2)/(3)* 60\\\\\\=40\ minutes`