Solved Examples and Worksheet for Elapsed Time

Q1Paul started playing tennis at 4:10 P.M. He played for 15 minutes. At what time did he stop playing?

A. 4:30 P.M.
B. after 15 minutes
C. 4:25 A.M.
D. 4:25 P.M.

Solutions
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Step: 1
4:10 is also read as 4 hours 10 minutes.
Step: 2
To find the time at which he stopped playing, we need to add 15 minutes to 4:10.
Step: 3
Hours  Minutes  
4  10  
+  15  
4  25  
  [Add.]
Step: 4
So, Paul stopped playing at 4:25 P.M.
Correct Answer is :   4:25 P.M.
Q2Jason started his homework at 5:20 P.M. He finished 30 minutes later. At what time did he finish his homework?

A. 5:50 P.M.
B. 5:50 A.M.
C. 5:30 P.M.
D. 5:55 P.M.

Solutions
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Step: 1
Jason started doing homework at 5:20 P.M.
Step: 2
He took 30 minutes to complete his homework.
Step: 3
The time at which Jason finished his homework = the time at which he started doing his homework + the duration of time in which he finished doing his homework.
Step: 4
  Hr  Min
  5:  20
+ 0:  30
_______
  5:  50
_______
Step: 5
So, Jason finished his homework at 5:50 P.M.
Correct Answer is :   5:50 P.M.
Q3Carol called her mom at 6:05 P.M. and spoke to her for 15 minutes. At what time did she end her call?

A. 6:20 P.M.
B. 6:15 A.M.
C. 6:15 P.M.
D. 6:20 A.M.

Solutions
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Step: 1
Carol called her mom at 6:05 P.M.
Step: 2
She spoke to her mom for 15 minutes.
Step: 3
The time at which Carol ends the call = the time of calling + the duration of time in which she spoke to her mom.
Step: 4
 Hr  Min
6:  05
0:  15
_______
6:  20
_______
Step: 5
So, Carol ended her call at 6:20 P.M.
Correct Answer is :   6:20 P.M.
Q4The duration of a flight journey is 40 minutes. The flight departed at 2:40 P.M. At what time will it reach the destination?

A. 2:35 P.M.
B. 3:35 P.M.
C. 2:20 P.M.
D. 3:20 P.M.

Solutions
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Step: 1
The duration of flight is 40 minutes.
Step: 2
The flight took off at 2:40 P.M.
Step: 3
The time at which the flight lands = the take off time + the duration of journey.
Step: 4
  Hr  Min
  2:   40
+ 0:  40
_______
 2:   80
_______
Step: 5
In 2:80, 2 is hours and 80 is minutes.
Step: 6
80 minutes = 60 minutes + 20 minutes.
Step: 7
So, 80 minutes is 1 hour 20 minutes.
  [Since 60 minutes = 1 hour.]
Step: 8
So, 2 hours 80 minutes = 3 hours 20 minutes.
  [Since 1 hour is added to 2.]
Step: 9
So, the flight lands at 3:20 P.M.
Correct Answer is :   3:20 P.M.
Q5Olga put a cake for baking in the oven at 4:10 pm. It would take about 50 minutes for the cake to be ready. At what time would the cake be ready?
A. 4:25 pm
B. 5:00 pm
C. 5:50 pm
D. 4:50 pm

Solutions
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Step: 1
Olga put the cake for baking in the oven at 4:10 pm.
Step: 2
The cake would be ready after 50 minutes.
Step: 3
So, the time when cake gets ready = the time at which the cake was put in the oven + the duration of time in which the cake would be ready.
Step: 4
  Hr  Min
  4:   10
+0:  50
_______
 4:   60
_______
  

[Add.]
Step: 5
4 hour 60 minutes = 4 hour + 1 hour = 5 hours
  [Since 60 minutes = 1 Hour.]
Step: 6
So, the cake would be ready at 5:00 pm.
Correct Answer is :   5:00 pm
Q6Jimmy was late for a movie by 25 minutes. If the movie started at 2.00 P.M., then at what time did Jimmy reach the theater?

A. 1:35 P.M.
B. 1:25 P.M.
C. 2:25 P.M.
D. 2:35 P.M.

Solutions
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Step: 1
The time at which Jimmy reached the theater = the time at which the movie started + the time by which he was late to the theater.
Step: 2
  Hr  Min
  2:   00
+ 0:  25
_______
 2:   25
_______
  [Add.]
Step: 3
So, Jimmy reached the theater at 2:25 P.M.
Correct Answer is :   2:25 P.M.
Q7What is the elapsed time between forty minutes after ten in the morning and twenty minutes after twelve in the noon?
A. 2 h 40 min
B. 1 h 20 min
C. 1 h 40 min
D. 2 h 20 min

Solutions
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Step: 1
Forty minutes after 10 is 10:40 = 10 h 40 min.
Step: 2
Twenty minutes after twelve is 12:20 = 12 h 20 min.
Step: 3
Elapsed time is the difference between forty minutes after ten and twenty minutes after twelve.
= 12 h 20 min - 10 h 40 min
  [Substitute the times.]
Step: 4
Elapsed time = 11 h 80 min - 10 h 40 min = 1 h 40 min.
  [12 h 20 min = 11 h (60 + 20) min = 11 h 80 min.]
[Subtract.]
Step: 5
Therefore, the elapsed time is 1 h 40 min.
Correct Answer is :   1 h 40 min
Q8Laura called her mom at 2:05 P.M. and spoke to her for 10 minutes. At what time did she end her call?

A. 2:15 P.M.
B. 2:10 P.M.
C. 2:10 A.M.

Solutions
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Step: 1
Laura called her mom at 2:05 P.M.
Step: 2
She spoke to her mom for 10 minutes.
Step: 3
The time at which Laura ends the call = the time of calling + the duration of time in which she spoke to her mom.
Step: 4
 Hr  Min
2:  05
0:  10
_______
2:  15
_______
Step: 5
So, Laura ended her call at 2:15 P.M.
Correct Answer is :   2:15 P.M.
Q9Anna wrote a math exam, which started at 8:00 a.m. She completed her exam in 45 minutes. At what time did she complete her exam?
A. 8:45 a.m.
B. 8:30 a.m.
C. 8:15 a.m.

Solutions
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Step: 1
The time at which Anna's exam started = 8:00 a.m.
Step: 2
The time she took to complete her exam = 45 minutes
Step: 3
The time at which she completed her exam = the time at which the exam started + the time she took to complete her exam
Step: 4
= 8:00 + 0:45 = 8:45 a.m.
Correct Answer is :   8:45 a.m.
Q10Ed started his homework at 3:15 p.m. He finished 20 minutes later. At what time did he finish his homework?
A. 4:30 p.m
B. 4:35 p.m
C. 3:30 p.m
D. 3:35 p.m

Solutions
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Step: 1
Start time = 3:15 p.m.
Step: 2
Time duration = 20 minutes
Step: 3

Step: 4
So, Ed finished his homework at 3:35 p.m.
Correct Answer is :   3:35 p.m
Q11Irena called her mother at 7:05 p.m. and spoke to her for 10 minutes. At what time did she end her call?
A. 7:15 p.m.
B. 7:15 a.m.
C. 7:10 p.m.
D. 7:10 a.m.

Solutions
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Step: 1
Start time = 7:05 p.m.
Step: 2
Time duration = 10 minutes
Step: 3

Step: 4
7:05 p.m. to 7:10 p.m = 5 minutes
7:10 p.m. to 7:15 p.m = 5 minutes
Step: 5
So, Irena ended her call at 7:15 p.m.
Correct Answer is :   7:15 p.m.

HighSchool Math