Page 145 - Start Up Mathematics_4

(b) The train is scheduled to depart at 10:30
in the morning.
(c) Ashish has invited his friend for dinner
at 9 o’clock.

(d) Tarun plans to watch a movie at 3:20 in
the afternoon.

Converting Hours into Minutes and Vice Versa Remember

We can convert the given hours into minutes and minutes The short forms of hours,
into hours by using the following. minutes and seconds are:
hour = h
1
1 hour (h) = 60 minutes (min) 1 minute = hours minute = min
60 seconds = s
Example 4: Convert the time in hours to minutes.
1
(a) 3 hours (b) 5 hours (c) 7 hours 30 minutes
2
Solution: (a) 3 h = (3 × 60) min = 180 min
1 1 Quick Tip
(b) 5 h = 5 h + h
2 2 To change hours to
1 minutes, multiply hours
= (5 × 60) min + × 60 min
2 by 60.

= 300 min + 30 min = 330 min
(c) 7 h 30 min = (7 × 60) min + 30 min = 420 min + 30 min = 450 min

Example 5: Convert the time in minutes to hours.
(a) 140 min (b) 240 min

140
Solution: (a) 140 min = 60 h

2 → hours
60 140
– 120
20 → minutes

So, 140 min = 2 h 20 min. Quick Tip

240
(b) 240 min = h To change minutes to
60 hours, divide minutes
4 → hours by 60.
60 240
– 240
0 → minutes

So, 240 min = 4 h.

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