Three number are in A.P, such that their sum is 18 and sum of there is 158. The greatest among them is

Options

A. 10
B. 11
C. 12
D. None of these

Answer

B

Explanation

Let the three numbers `(a-d),` and `(a+d)` in AP. Then
`(a-d)+a+(a+d)=18`
`impliesa=6`…….i
and `(a-d)^(2)+a^(2)+(a+d)^(2)=158`
`implies3a^(2)+2d^(2)=158`
`implies3a^(2)+2d^(2)=158`
`implies2d^(2)=158-3xx36` [from eq (i) ]
`:. d=+-5`
So, the required numbers are 1,6, 11 or 11,6,1.
Thus greatest number is 11.