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

Question

asked Jul 2, 2017 71.8k views

2 Answers

Paul Ghiran · Answer 1 · 2017-07-07T05:25:22+0000

Let x be the first even number. Then adding 2 consecutively gives us the subsequent even numbers. That is

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

From the question, the mean of these four numbers is 15. That is;

$(\sum x)/(n) =15$

$\Rightarrow (x+(x+2)+(x+4)+(x+6))/(4) =15$

$\Rightarrow (x+x+2+x+4+x+6)/(4) =15$

$\Rightarrow (x+x+x+x+2+4+6)/(4) =15$

$\Rightarrow (4x+12)/(4) =15$

Multiply both sides by 4 to obtain,

$\Rightarrow 4* (4x+12)/(4) =4 *15$

$\Rightarrow 4x+12 =60$

$\Rightarrow 4x =60-12$

$\Rightarrow 4x =48$

Divide both sides by 4 to obtain,

x =12