An urn contains six chips, numbered 1 through 6. two are chosen at random and their numbers are added together. what is the probability that the resulting sum is equal to 5?

2/15 if drawn without replacement. 1/9 if drawn with replacement. Assuming that the chips are drawn without replacement, there are 6 * 5 different possibilities. And that's a low enough number to exhaustively enumerate them. So they are: 1,2 : 1,3 : 1,4 : 1,5 : 1,6 2,1 : 2,3 : 2,4 : 2,5 : 2,6 3,1 : 3,2 : 3.4 : 3,5 : 3,6 4,1 : 4,2 : 4.3 : 4,5 : 4,6 5,1 : 5,2 : 5.3 : 5,4 : 5,6 6,1 : 6,2 : 6.3 : 6,4 : 6,5 Of the above 30 possible draws, there are 4 that add up to 5. So the probability is 4/30 = 2/15 If the draw is done with replacement, then there are 36 possible draws. Once again, small enough to exhaustively list, they are: 1,1 : 1,2 : 1,3 : 1,4 : 1,5 : 1,6 2,1 : 2,2 : 2,3 : 2,4 : 2,5 : 2,6 3,1 : 3,2 : 3,3 : 3.4 : 3,5 : 3,6 4,1 : 4,2 : 4.3 : 4,4 : 4,5 : 4,6 5,1 : 5,2 : 5.3 : 5,4 : 5,5 : 5,6 6,1 : 6,2 : 6.3 : 6,4 : 6,5 : 6,6 And of the above 36 possibilities, exactly 4 add up to 5. So you have 4/36 = 1/9

Okay so for every triangle has three angles that always add up to 180 degrees. and to tell the difference between whether they are secure, right or obtuse is that acute: has one angle that is less than 90 degrees. right triangle means there is at least one angle that is exactly 90 degrees. and an obtuse angle has an angle that is bigger than 180 degrees. i’ll do #13 as an example: 13. 40 and 50 so if every triangle has 180 degrees 40+50= 90 degrees then180-90= 90 degrees so the third angle is 90 degrees and because this triangle has a 90 degree angle it means it is a right triangle