Convert $1\dfrac{1}{2}$ hour into seconds.
(a)3600 seconds
(b)1800 seconds
(c)7200 seconds
(d)5400 seconds

Hint: Change the time from mixed fraction to a simple fraction. And use the following relations between hour and minutes, and minutes and seconds.

Complete step-by-step answer:

There are 60 minutes in one hour.

There are 60 seconds in one minute.

Hence, get the time in seconds with help of above statements.


As, we know the number of seconds in one minute is 60 and the number of minutes in one hour is 60 as well.

As, we need to convert a given time $1\dfrac{1}{2}$ hour to the seconds.

So, let us first convert the time in hours to minutes and hence, in seconds.

So, we know that there are 60 minutes in 1 hour. We can write equation as,

$1hour=60$ minutes ………………………………(i)

Now, as the given time in hour is in mixed fraction, we can get time in simple fraction as,

$1\dfrac{1}{2}hour=\dfrac{1\times 2+1}{2}=\dfrac{3}{2}hour$

Now, we can use equation (i) and can get time $\dfrac{3}{2}$ hour in minutes.

So, we have

$1hour=60$ minutes

Hence, $\dfrac{3}{2}hour=60\times \dfrac{3}{2}=30\times 3=90$ minutes.

$\Rightarrow \dfrac{3}{2}hour=90$ minutes ……………………………..(ii)

Now, as we know there are 60 seconds in one minute, so, we can get an equation as

1 minute $=$ 60 seconds

Hence, 90 minutes will have number of seconds as

1 minute $=$ 60 seconds

90 minutes $=90\times 60=5400$ seconds.

Hence, time $1\dfrac{1}{2}hour$ will be equal to 90 minutes and 90 minutes is equal to 5400

seconds. Hence, $1\dfrac{1}{2}hour$ will be equal to 5400 seconds.

Hence, option (d) is correct.

Note: One may directly multiply the given time in hours by 3600 as well, as there are 3600 seconds in one 1 hour. So, it can be another approach as well.

Don’t confuse it with the mixed fraction, first convert it to a simple fraction then proceed further.