202110794-TRAVELLER_PREMIUM-STUDENT-TEXTBOOK-MATHEMATICS-G05-PART1

Example 13: A courier boy delivered letters for 2 hours 35 minutes and parcels for 3 hours 28 minutes in a day. For how long was he on the job? Solution: Time spent on delivering letters = 2 h 35 min Hours Minutes 2 35 Time spent on delivering parcels = 3 h 28 min + 3 28 5 63 Total time spent on the job = 2 h 35 min + 3 h 28 min = 5 h 63 min 63 > 60 63 min = 1 h 3 min Therefore, the total time spent on the job = (5 h + 1 h) + 3 min = 6 h 3 min. Example 14: On a Saturday, Rima’s drawing class lasted for 2 hours 20 minutes, while on the following Sunday, it lasted for 1 hour 40 minutes. How much longer was the drawing class on Saturday? Solution: To find how much longer the drawing class on Saturday was, we must subtract 1 hour 40 minutes from 2 hours 20 minutes. We borrow 60 minutes (1 hour) and add to the minutes. Hours Minutes 1 80 –1 40 0 40 Therefore, on Saturday Rima’s drawing class lasted 40 minutes longer. Let us also look at some examples of multiplication and division of time. Example 15: Bharat takes 15 minutes to read a page of a novel. How much time will he take to read 5 pages of the same novel? Solution: Time taken by Bharat to read a page of a novel = 15 minutes. To find how much time he takes to read 5 pages of the novel, we must multiply the time taken for him to read a page by 5. 75 minutes can be written as 1 h 15 min. 15 x5 Therefore, Bharat takes 1 h 15 min to read 5 pages of the 75 novel. Time 97

Example 16: In a week, Palak spends 280 minutes at her guitar class. If she spends the same amount of time every day, how much time does she spend in a day at the guitar class? Solution: To find how much time Palak spends at the guitar class every day, we must divide the time she spends in a week by 7. Time spent by Palak every day at the guitar class = 280 ÷ 7 min = 40 min Therefore, Palak spends 40 min every day at the guitar class. I Explore (H.O.T.S.) Example 17: Mr. Roy spends 1 hour 30 minutes in his garden every day. Mr. Pavan does the same for 50 minutes. How much more time does Mr. Roy spend than Mr. Pavan in his garden? Give your answer in seconds. Solution: Time spent by Mr. Roy in his garden = 1 hour 30 minutes Time spent by Mr. Pavan in his garden = 50 minutes To find the required difference, subtract 50 minutes from 1 hour 30 minutes. Now, we need to find the answer in seconds. Hours Minutes 1 minute = 60 seconds 1 30 40 minutes = 40 × 60 seconds = 2400 seconds –0 50 0 40 Therefore, Mr. Roy spends 2400 seconds more in his garden than Mr. Pavan. Example 18: Sohan started preparing for his exams on 16th July. The exams were scheduled to begin 25 days later. On which date were the exams scheduled to begin? Solution: Start date of exam preparation = 16th July Preparation day for exams includes 16th July. So, subtract 15 days from 31 days of July. Number of days of preparation in July = 31 – 15 = 16 Days of preparation left in August = 25 – 16 = 9 Therefore, the date when the exams begin is 10th August. 98

Maths Munchies The same date every year falls on consecutive days of the week. For example, if 4th February of this year falls on a Saturday, the next year it will fall on a Sunday. However, if the current month falls in a leap year with 29th February coming in between, then the difference in days increases to two days. For example, 4th March 2015 fell on a Wednesday, whereas 4th March 2016 fell on a Friday. This is because 2016 was a leap year. Connect the Dots Social Studies Fun Our universe is 13.8 billion years old. If 10 years is known as a decade, what are 100 years and 1000 years known as? How many decades old is our universe? Science Fun Mayfly is the type of insect which has the shortest life-span. It is also called as ‘one-day insect’. Drill Time 6.1 Convert Time b) 3 years 10 days c) 2 years 15 days e) 1 year 3 weeks 1) Convert into days. a) 4 years 5 weeks d) 4 years 20 days Time 99

2) Convert the given time to hours. a) 240 minutes b) 361 minutes c) 139 minutes d) 3600 seconds 3) Word problems a) A bus takes 1 hour and 25 minutes to reach a bus stand. It stops 5 times for 45 seconds at each stop to pick up passengers. For how many minutes did the bus stop? b) Amit reached his house from school in 120 minutes. Find the time taken by Amit to reach his house in hours. 6.2 Add and Subtract Time 4) Add: a) 2 hours 40 minutes and 1 hour 33 minutes b) 3 hours 26 minutes and 2 hours 22 minutes c) 4 hours 31 minutes and 1 hour 28 minutes 5) Subtract: a) 1 hour 30 minutes from 3 hours 25 minutes b) 2 hours 20 minutes from 5 hours 45 minutes c) 1 hour 40 minutes from 6 hours 49 minutes 6) Word problems a) S unil takes 2 hours 30 minutes to complete his homework and Aditya does the same homework in 145 minutes. Who takes less time to complete his homework? b) P reeti spends 70 minutes in the playground and Ajit spends 1 hour 900 seconds in the playground. How much more time does Ajit spend than Preeti in the playground? A Note to Parent Show your child a railway or an airline ticket which has the arrival and departure times printed on it. Help them to calculate the time taken for the journey. 100