Answer:

Step-by-step explanation:
The error in rounding a number is half of the unit of measure.
The number was rounded to the nearest 0.1 unit so the error is 1/2×0.1, which equals 0.05.
Now we add 3.7 and 0.05, which equals 3.75 and we also take 3.7 - 0.05, which equals 3.65
So, the error interval is:

No it is undefined when the number reaches to zero.
Answer:
15
Step-by-step explanation:
3 and 5 are not common denominators so you have to find the lowest common denominator which is 15 because 3 times 5 is 15