Agirl scout is selling cookies. she currently has 3 boxes of thin mints, 4 boxes of tag-alongs, and 5 boxes of somoas left. what is the probability that a customer will randomly buy two of the same box of cookie to purchase?

Probability that customer will buy 2 boxes of Thin Mints: 3/12*2/11=6/132
Probability that customer will buy 2 boxes of Tag-Alongs: 4/12*3/11=12/132
Probability that customer will buy 2 boxes of Somoas: 5/12*4/11=20/132
Thus the probability in total is 6/132+12/132+20/132=28/132=28.7879%

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)