Question 332256
Hint: "The average of x, y, and z is 80 " means that {{{(x+y+z)/3=80}}}. We're given that "two of the numbers are 74 and 78", so let {{{x=74}}} and {{{y=78}}} and plug them in to get {{{(74+78+z)/3=80}}}. Now solve for 'z' to find the missing number.