The answer to this math problem is 4
The rule of the pattern is the numbers are all ascending by 3.
{ 2 , 5 , 8 , 11 , 14 , 17 , 20 }
Now what you want to do is 21 + (-3). Since this is the same as saying 21 - 3, the answer is 18. Therefore, the answer is 18°F.
There would be 107 whistles
-equation- 235-128=107
