Adding minutes to a clock time

Difficulty Standard · Set gtz76c

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1
A film starts at 10:05 and lasts 155 minutes. What time does it end? Give it as hh:mm.
2
A film starts at 10:25 and lasts 140 minutes. What time does it end? Give it as hh:mm.
3
A film starts at 09:30 and lasts 195 minutes. What time does it end? Give it as hh:mm.
4
A film starts at 15:55 and lasts 140 minutes. What time does it end? Give it as hh:mm.
5
A film starts at 20:30 and lasts 200 minutes. What time does it end? Give it as hh:mm.
6
A film starts at 16:10 and lasts 170 minutes. What time does it end? Give it as hh:mm.
7
A film starts at 11:45 and lasts 135 minutes. What time does it end? Give it as hh:mm.
8
A film starts at 15:30 and lasts 185 minutes. What time does it end? Give it as hh:mm.
9
A film starts at 16:25 and lasts 125 minutes. What time does it end? Give it as hh:mm.
10
A film starts at 09:00 and lasts 165 minutes. What time does it end? Give it as hh:mm.
11
A film starts at 15:20 and lasts 140 minutes. What time does it end? Give it as hh:mm.
12
A film starts at 17:25 and lasts 140 minutes. What time does it end? Give it as hh:mm.
13
A film starts at 14:30 and lasts 175 minutes. What time does it end? Give it as hh:mm.
14
A film starts at 15:50 and lasts 100 minutes. What time does it end? Give it as hh:mm.
15
A film starts at 19:10 and lasts 190 minutes. What time does it end? Give it as hh:mm.
16
A film starts at 10:50 and lasts 155 minutes. What time does it end? Give it as hh:mm.
17
A film starts at 16:05 and lasts 160 minutes. What time does it end? Give it as hh:mm.
18
A film starts at 14:50 and lasts 110 minutes. What time does it end? Give it as hh:mm.
19
A film starts at 12:15 and lasts 150 minutes. What time does it end? Give it as hh:mm.
20
A film starts at 09:00 and lasts 125 minutes. What time does it end? Give it as hh:mm.

What is in this set

The numbers in this set run from 5 to 200.
52% of them stay inside the same hour.
48% of them cross an hour boundary.
A careful solution takes 3 written steps on average.
The mistake this set invites most often, in 48% of the problems: the minutes went past 60 and were written as they stood.
Answers are a short answer exactly as the problem asks for it.

Drawing 240 problems from this page produced 235 different ones, 98% — so a sheet of 20 is a new sheet almost every time.

The same skill, harder or easier

We would put this in front of a grade 4 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.