Afair coin is tossed 12 times. what is the probability that at least two heads appear

In the rectangle below ac=30 units what is de

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)