My work:

There are 24 hours in one day.

There are 60 minutes in one hour.

So, 24 x 60 = 1440 minutes in one day.

There are 60 seconds in one minute.

So, 1440 x 60 = 86,400 seconds in one day.

0.15/86,400 = 0.60/x

(86,400)(0.60) = (x)(0.15)

51,840 = x(0.15)

51,840/0.15 = x

345,600 = x

345,600/86,400 = x

4 minutes = x

OR

Is it this way:

86,400/0.15 = 576,000

576,000/1440 = 400 minutes