Three times a first number minus a second number equals negative forty the first number plus twice the second number equals negative forty

Distance traveled = 70 m
Number of rotations = 35

We know, Circumference * Number of rotations = Distance traveled
So, C = 70 / 35
C = 2 m

Now, we know, diameter = C / π
So, d = 2/3.14 = 0.64 m

In short, Your Answer would be: 2/π m or 0.64 m

Hope this helps!