one task takes 7 mins
second task takes 12 min
third task takes 21 nin
how long dids the 3 tasks take, as a fraction of a hour
7/30+12/30+21/30=40/30 =1 1/3 hr
is that right?
no 2/3
Prinness is correct. There are 60 minutes (not 30) in an hour. So -- your answer would be 40/60 = 2/3 hour.
To calculate the total time taken by the three tasks as a fraction of an hour, you need to convert the individual task times from minutes to hours and then add them together.
The conversion factor to convert minutes to hours is 1/60, since there are 60 minutes in an hour.
The first task takes 7 minutes, so in hours, it would be 7/60.
The second task takes 12 minutes, so in hours, it would be 12/60.
The third task takes 21 minutes, so in hours, it would be 21/60.
Now, add these fractions together:
7/60 + 12/60 + 21/60 = 40/60 = 2/3
Therefore, the three tasks take 2/3 of an hour or 40 minutes.