Question 413892
If you consider the 4 exams with the lowest removed you will see that the average is 70, so this lets you know that on these four there was a total or 280 (70 x 4) scored.  

Now with all 5 you can see the average was 67, so this means you scored a total of 335 on all 5 (67 x 5).  You know you got 280 on the other four, so to find out now just subtract the 280 away from the 335 to find that the last score was 55.