Greg has decreased his running time by 1/10 minute each of the last six weeks. Write an expression to represent the total change in his time over the last six weeks. Then, find the total change.

Total change = x - 36 seconds.

Step-by-step explanation:

Let Greg's initial running time be x seconds.

Also, 1/10 minute = 6 seconds.

In the first week, his running time = x - 6

In the second week, his running time = x - 6 - 6 = x - 2 (6)

In the third week, his running time = x - 6 - 6 - 6 = x - 3 (6)

...

...

In the sixth week, his running time = x - 6 (6) = x - 36

Hence, the total change = x - 36.

x is your starting running time. 1/10 of a minute is 6 seconds, so you can do x - 6 (6). 6 times 6 = 36, so your answer is x - 36 seconds. 36 seconds.