If usain bolt ran the 100 meter dash in 9.58 seconds. if he ran at a constaint rate how many meters did he run in 3 seconds

The best thing to do is to find the unit rate per second then multiply accordingly.
What you have to do now is to divide 100 by 9.58 to find the unit rate per second.
100/9.58= 10.44 metres per second (rounded to 2dp)
Then to find 3 seconds, you multiply this by 3.
10.44*3= 31.32 metres
This therefore mean he ran 31.32 metres in 3 seconds
Hope this helps :)