Answer: it took him 0.075 seconds lesser
Step-by-step explanation:
In his first heat, his time was 2.45 seconds greater than his friend's record time. In his second heat, his time was 2 3/8 seconds greater than his friend's record time. Converting 2 3/8 seconds to decimal, it becomes 2.375 seconds
Therefore, he was fastest in the second heat.
The difference between the time he used to run in the second heat than in the first heat is
2.45 - 2.375 = 0.075 seconds