(30+X)/2=60
(30+X)=120
X=90
What is the purpose of this if I may ask?
The first equation "(30+X)/2=60" would be:
(30 miles/hour + x miles/hour)/2 miles = 60 miles /hour
which is
15/hours + x/2 hours = 60 miles/hour.
Note the inconsistent unit of miles instead of miles per hour.
(This is probably wrong. It's after 3 am here
)