Answer:
450
Explanation:
We know that Cole did jump rope for 7 1/2 minutes.
In one minute there are 60 seconds. So we know that for each minute there is a 60 in it.
So, 7 x 60 = 420 then a half minute is thirty seconds (we know this because half of sixty is thirty.)
So we simply add 30 to 420 getting 450.