To find the time the fourth runner must beat in order for the total time to be less than 60 seconds, we'll start by calculating the total time of the first three runners.
The times for the first three runners are:
- First runner: 14.7 s
- Second runner: 16.2 s
- Third runner: 15.3 s
Let's calculate the total time of the first three runners:
\[ 14.7 + 16.2 + 15.3 = 46.2 \text{ seconds} \]
Next, we need the total time of all four runners to be less than 60 seconds. Let's denote the time of the fourth runner as \( x \). Therefore, we can set up the following inequality:
\[ 46.2 + x < 60 \]
Now, we'll isolate \( x \):
\[ x < 60 - 46.2 \] \[ x < 13.8 \text{ seconds} \]
Thus, the fourth runner must beat 13.8 seconds in order for the total time to be less than 60 seconds.
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