Four coins are thrown together,what are probability of i. At least two coin and ii. At most three coins

let 'S' a sample space ,then card(S)=16.

i)At last two coin : P=(2C4+3C4+4C4)/card(S)=11/16

ii)At most three coins:P=(1C4+2C4+3C4)/card(S)=14/16