The average of 7, 11, 15, \(x\), 14, 21 and 25 is 15. What is the value of \(x\)?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 12
The sum of the numbers is the average multiplied by how many numbers there are; the missing number is that sum minus the known numbers.
There are 7 numbers, so their sum \(=7\times15=105\)
Sum of the known six \(=7+11+15+14+21+25=93\)
\(x=105-93=12\)
The value of \(x\) is 12.