express each rate as a unit rate.

400 yards in 53 seconds

(400/53) yards/second

400/53=7.55

To express a rate as a unit rate, we need to find the value of 1 unit of the given quantity. In this case, we want to express the rate of 400 yards in 53 seconds as a unit rate.

To do this, we divide the quantity by the given value. Here's the calculation:

400 yards ÷ 53 seconds

When we divide 400 yards by 53 seconds, we get approximately 7.547 units.

Therefore, the unit rate for 400 yards in 53 seconds is approximately 7.547 yards per second.