1.

The common difference of the divisible byA. 1B. 3C. 2D. `-2`

Answer» Correct Answer - A
Let the four integers be a-d,a,a+d, and a+2d, where a and d are integers and `dgt0`. Now,
`a+2d=(a-d)^(2)+a^(2)+(a+d)^(2)`
or `2d^(2)-2d+3a^(2)-a=0` (1)
`therefored=1/2[1pmsqrt(1+2a-6a^(2))]` (2)
Since d is a positive integer, so
`1+2a-6a^(2)gt0`
or `6a^(2)-2a-1lt0`
or `(1-sqrt7)/6ltalt(1+sqrt7)/6`
or a=0 (`because` a is an integer)
Hence, from (2),
d=1 or 0
But since `dgt0`,
`therefore` d=1
Hence, the four numbers are -1,0,1,2.


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