Problema Solution
I have a list of 5 numbers whose mean is 12. If I remove one of the numbers, the mean becomes 13. What is the value of the number I removed?
Answer provided by our tutors
let 'x' represent the number that gets removed and 't' represent the total, or sum, of the other four numbers, then we know that:
a list of 5 numbers whose mean is 12:
(t+x)/5 = 12
If I remove one of the numbers, the mean becomes 13, so we remove 'x' and we can solve for 't':
t/4 = 13
t = 52
we revisit the first equation, substituting 't' with '52' and solving for 'x':
(52+x)/5 = 12
x = 8
the number that was removed is 8