Please help probability

Question

In 10 tosses of a coin, what is the probability of getting not less than 3 heads and not more than 6 heads?

Answer 1

probability of getting not less than 3 heads and not more than 6 heads out of 10 tosses of a coin

P(3≤x≤6)=P(3)+P(4)+P(5)+P(6)

             =10C3+10C4+10C5+10C6

             =(10!/(7!*3!)+(10!/(6!*4!)+(10!/(5!*5!)+(10!/(4!*6!)

             =120+210+252+210

            =792