3.1 is like a example when it is hiding a zero behind it and you find this when you do a math problem and you don't put zero in front of a number like 100-89 you don't write "011" so that is why it is like that
I think it’s 4 m because diameter is 2r
The average speed is given by:
average speed=(total distance)/(total time)
total time for the first 30 miles was:
time=distance/speed
=30/30
=1 hr
total time for the remaining 30 miles
=30/60
=0.5
hence the average speed will be:
speed=(30+30)/(1+0.5)=60/1.5=40 miles per hour
Here is the work:
(13x - 5x) + 12 - 2y = 6
(8x) + 12 - 2y = 6
-2y = -8x - 12 + 6
-2y = -8x - 6
y = 4x + 3