Amountain bike tire completes 20 revolutions and travels 136 feet. rounded to the nearest inch, what is the diameter of the bike’s tire? use 3.14 for π

We know that
one revolution is equal to the circumference of a circle
circumference C=pi*D
where 
D is the diameter of a circle

step 1
divide 136 ft by 20 revolutions
so
136/20=6.8 ft
that means one revolution is 6.8 ft
C=6.8 ft
C=pi*D
pi*D=6.8> divide by pi both sides> D=6.8/pi
D=6.8/3.14> D=2.166 ft
convert to in
1 ft> 12 in
2.166 ft> x
x=2.166*12> x=25.98 in> 26 in

the answer is
The diameter is 26 in

Step 1: 6x-10=1; step 2: 6x=11