Let us consider some of the word problems on measurement of time i.e. hours, minutes and seconds.
Examples on addition of hours, minutes and seconds:
1. A train leaves Delhi for Tundla at 7:30 a.m. It takes 5 ours to reach at Tundla. At what time it reach at Tundal?
The train departs at hr. min.
Time taken to reach at Tundla 7 30
The train will reach at Tundla + 5 00
Therefore, the train will reach Tundla at 12:30 p.m.
2. Sam leaves for school at 6:35 a.m. It takes him 1 hr. 45 min. to reach the school. At what time will he reach the school?
Sam leaves for school at hr. min.
Time taken to reach the school 6 35
Sam will reach the school at + 1 45
7 hr. 80 min. = 7 hr. + 60 min. + 20 min.
= 7 hr. + 1 hr. + 20 min.
= 8 hr. 20 minutes.
Therefore, Sam will reach the school at 8:20 a.m.
Examples on subtraction of hours, minutes and seconds:
1. Ron left for his school at 6:35 a.m. He reached the school at 8:25 a.m. How much time did Ron take to reach the school?
Ron reached his school at 7:25 a.m.
He left for his school at 6:35 a.m.
Time taken by him to reach the school
= 7 hr. 25 min - 6hr. 35 min
= 0 hr. 50 min.
Therefore, time taken by Ron to reach the school is 50 minutes.
2. Ken left his home at 4:30 p.m. to play cricket. He came at 7:15 p.m. How long was he away from his home?
Ken came back at 7:15 p.m.
He left home at 4:30 p.m.
He was away from home = 7 hr. 15 min. - 4 hr. 30 min.
= 2 hr. 45 min.
Therefore, Ron was away from home 2 hours 45 minutes