Elmer has taken n tests. If he receives 73 on the next test, his average will be exactly 83. If he receives 99, then the average will be exactly 87. What does n equal?
It seems to work for n = 5 tests before the last. But the average of 87 comes out as 87 1/3 !! Did you make a mistake somewhere in the question?
+33615 "Elmer has taken n tests. If he receives 73 on the next test, his average will be exactly 83. If he receives 99, then the average will be exactly 87. What does n equal?"
(x + 73)/(n + 1) = 83 ...(1)
(x + 99)/(n + 1) = 87 ...(2)
Rewrite (1) as x + 73 = 83*(n + 1) ...(3)
and (2) as x + 99 = 87*(n + 1) ...(4)
Subtract (3) from (4): 26 = 4n + 4 so n = 5.5 Elmer took 5.5 tests??????
