Answer: Total change= 36 seconds.
Step-by-step explanation:
Let Greg's initial running time be t seconds.
As Greg has decreased his running time by 1 tenth minute each week.
Now, 1 tenth of minute =\(\frac{1}{10}\times60=6\ seconds\)
Thus In the first week, his running time = \(t-6\)
In the second week, his running time =\(t-6-6=t-12=t-2(6)\)
Similarly,
In the sixth week, his running time =\(t-6(6)=t-36\)
Hence, the total change in time of running = 36 seconds
