Kerri ran the same distance in four different races. Her times were 18.04 seconds, 21.39 seconds, 12.99 seconds, and 14.14 seconds. If the individual times are rounded to the nearest one-tenth of a second, what is the estimate of Kerri's total time for all four races?

16.64 average of the four races that kerri ran in seconds.

The estimate rounded to the nearest one-tenth of a second is 66.6 seconds

Step-by-step explanation:

To find the total time T for all of the four races, we sum the time of each race.

So T = 18.04+21.39+12.99+14.14 = 66.56 seconds.

Now we have to round to the nearest one-tenth of a second, which is the first decimal value.

If the second digit was between 0 and 5 (it means 66.50, 66.51, 66.52, etc) the total time would be rounded to 66.5 seconds

Since the second digit is 6, the time is rounded to 66.6 seconds.