How many times 90 degree angle is formed Between 4pm 10pm?

Answer 1

I'll go out on a limb here, make a possibly unwarranted assumption, rush in with

no concern for my personal welfare to a place where angels fear to tread, and

presume that you're talking about the angle formed by the hour- and minute hands

of an old fashioned clock.

On that assumption, I count eleven (11) of them.