Five students wrote a mathematics test. The average mark was 68. If the marks for four of the students were 75, 62, 84 and 53, the mark of the fifth student was A) 66 B) 68 C) 76 D) 68.5 E) 56
If x is the mark for the fifth student, then: (75 + 62 + 84 + 53 + x)/5 = 68 or (274 + x)/5 = 68
Rearrange this to find x.
+46 
