Question

the mean of four consecutive even numbers is 15.the greatest of these numbers is a1.the least of these numbers is a2.

Answer 1

`\frac{x+(x+1)+(x+2)+(x+3)}4=\frac{4x+6}4=15\implies 4x+6=60\implies 4x=54\implies x=9`

which means
`a_1=x=9` and
`a_2=x+3=12`

Answer 2

Answer: The greatest no a1 is 18 and smallest no a2 is 12

Explanation:

Let the consecutive even numbers be

x, x+2 , x+4 , x+6

Given mean of four nos =15

Now mean = Sum of all observations/No of observations

15 =
`(x+x+2 + x+4 +x + 6)/(4)`

4x +12 =15×4

4x + 12 = 60

Subtracting 12 both sides

4x + 12- 12 =60 - 12

4x = 48

Dividing both sides by 4

x=12

Hence the smallest no i.e. a2 is 12

Other nos be 12 +2 =14, 12+4 =16, 12 +6= 18

The greatest no i.e. a1 = 18

Hence the nos are 12, 14, 16, 18