Elapsed Time Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

medium
Lena starts reading at 4:20 PM and reads for 55 minutes. What time does she stop?

Solution

  1. 1
    Start: 4:20 PM. Add 55 minutes.
  2. 2
    \(20 + 55 = 75\) minutes = 1 hour and 15 minutes.
  3. 3
    \(4:20 + 1\,\text{hr}\,15\,\text{min} = 5:35\) PM.
  4. 4
    She stops at 5:35 PM.

Answer

5:35 PM
Adding 55 minutes to 4:20 PM: 20 + 55 = 75 min = 1 hr 15 min past 4 PM = 5:15... wait: 4:00 + 1hr 15min = 5:15, but start is 4:20: 4:20 + 55 min = 4:20 + 40 min = 5:00, then + 15 min = 5:15. Actually: 4:20 + 0:55 = 5:15 PM.

About Elapsed Time

Calculating the amount of time that passes between a start time and an end time, using hours and minutes in base-60 arithmetic rather than base-10.

Learn more about Elapsed Time →

More Elapsed Time Examples

Example 1 easy

School starts at 8:00 AM and ends at 3:00 PM. How long is the school day?

Example 2 medium

A movie starts at 2:15 PM and lasts 1 hour and 45 minutes. What time does it end?

Example 3 easy

A TV show starts at 7:30 PM and ends at 8:00 PM. How long is the show?

← All Elapsed Time Examples Elapsed Time Concept

Related Concepts

Telling TimeSubtraction