This is the same as 31 7/12 minutes
It's a mixed number with
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Explanation
I'll use an ampersand symbol to separate the whole part from the fractional part.
For instance 1 1/3 will be written as 1 & 1/3
Rewrite each mixed number so that the fractional part has the LCD 12 (since 3*4 = 12).
We then subtract the last two values to find how long the 2nd place runner took.
(34 & 8/12) - (1 & 9/12)
(34 + 8/12) - (1 + 9/12)
(33 + 1 + 8/12) - (1 + 9/12)
(33 + 12/12 + 8/12) - (1 + 9/12)
(33 + 20/12) - (1 + 9/12)
33 + 20/12 - 1 - 9/12
(33 - 1) + (20/12 - 9/12)
32 + (11/12)
32 & 11/12
In short,
(34 & 8/12) - (1 & 9/12) = 32 & 11/12
Therefore, the 2nd place runner took 32 & 11/12 minutes. You can use WolframAlpha to confirm.
For the last batch of steps, we subtract (32 & 11/12) and (1 & 4/12) to find the time value of the 1st place runner.
(32 & 11/12) - (1 & 4/12)
(32 + 11/12) - (1 + 4/12)
32 + 11/12 - 1 - 4/12
(32 - 1) + (11/12 - 4/12)
31 + (7/12)
31 & 7/12 which is the final answer
You can write the answer as 31 7/12 if you wanted.