so what i did was that i divided 65/13 and i got 5 and then i divided 5/2 and got 2.5 and then i multiplied 13 and 2.5 and got 32.5 and then i divided 32.5 and 2.5 and got 65 and then i multiplied 65 and 2.5 and got 162.5
Probability of a tail for any on coin = 1/2 As the tosses of the 4 coins are independent of each other we multyiply the probs:- P(4 tails) = 1/2 * 1/2*1/2*1/2 = 1/16