Question 996812
average=total/number
number*average=total
total must be between 225 and 270, those coming from multiplying 3 by 75 and 90 respectively.
current total is 161.
the score x, when added to 161 has to be between 225 and 270.  But x can't be greater than 100.
225<=161+x<=270
or
64 <= x<= 100, since a score of 109 can't be obtained.