Respuesta :
Let Yesenia's score in the third test be represented by the letter "x".
Now, we know that, by definition, the average in our case is the ratio of the sum of the points scored in the tests to the total number of tests taken.
We know that Yesenia scored 91 points on her first test and 73 points on her second test.We also know that Yesenia's average is 79. We have already assumed that she scored "x" in the third test. Thus, by definition of average, we get the following equation as:
[tex] 79=\frac{91+73+x}{3} [/tex]
Cross multiplication gives us:
[tex] 79\time 3=164+x [/tex]
Thus, [tex] x=237-164=73 [/tex]
Thus, Yesenia got a score of 73 in her third test.