If 3 coins are tossed are together,find the probability that at least one of the coins show head. please explain it clearly

total outcome = 6C3 = 20
favourable outcomes (none is head)=3C3 = 1
required probability = 1- 1/20 = 19/20

In single coin toss head and tail has equal probability = 1/2
now,
in our problem we need at least 1 head ;
so, non-favorable case is occurrence of all 3 tail.

so, answer will be (1- probability of all tails)
probability of all tails = (1/2) X (1/2) X (1/2) =1/8.

probability of at least one head = 1-(1/8) =7/8.