Question

Thanh has scores of 54, 83, 67, and 73 on his first four math exams. What score must he make on the fifth exam to have an average of 70 or better for the five exams?

Answer 1

To solve this, you would set up the equation to find the arithmetic mean of the data. This equation is (53+83+67+73+x)/5=70, where x=the score of the fifth exam. First, you combine the constants to get (276+x)/5=70. Then, multiply both sides by 5 to get rid of the denominator, to give you 276+x=350. Then subtract 276 from each side to get x=74. So, Thanh needs to score a 74 on his last exam to get a 70 in the class.