The difference between the averages of three consecutive even numbers and the average of the next two consecutive even numbers is 5. What is the first even number ?
The difference between the averages of three consecutive even numbers and the average of the next two consecutive even numbers is 5. What is the first even number ?
1). 10
2). 12
3). 14
4). Can’t be determined
2 answers
Let the five even numbers be a, a+2, a+4, a+6 and a+8.
Hence, the average of the first three even numbers is (a+a+2+a+4)/3 = a+2
The average of the next two even numbers is (a+6+a+8)/2 = a+7
Hence, their difference is (a+7)-(a+2) = 5
This is always the same irrespective of the value of a. Hence, it can't be determined.
Let the five even numbers be a, a+2, a+4, a+6 and a+8.
Hence, the average of the first three even numbers is (a+a+2+a+4)/3 = a+2
The average of the next two even numbers is (a+6+a+8)/2 = a+7
Hence, their difference is (a+7)-(a+2) = 5
This is always the same irrespective of the value of a. Hence, it can't be determined.