edited by
11,706 views

2 Answers

Best answer
32 votes
32 votes
$\sqrt{(224)_r} = (13)_r$

Converting $r$ base to decimal

$\sqrt{2\times r^2 + 2\times r + 4} = 1 \times r + 3$

Take square on both sides

$2r^2 + 2r + 4 = r^2 + 6r+ 9$

$\implies r^2 - 4r -5 = 0$

$\implies r^2 -5r +r - 5 = 0$

$\implies (r-5)(r+1)=0$

$r$ being a base, it can not be $-1.$

So, $C.$ $r = 5$ is correct answer
edited by
3 votes
3 votes
In such type of question s always  convert unknown  base  given  i.e base  b,  to decimal  i.e base 10  and  perform operations  simple concept  so answer is 5
Answer:

Related questions

39 votes
39 votes
9 answers
2
Kathleen asked Sep 29, 2014
15,653 views
Let $f(x, y, z)=\bar{x} + \bar{y}x + xz$ be a switching function. Which one of the following is valid?$\bar{y} x$ is a prime implicant of $f$$xz$ is a minterm of $f$$xz$ ...
37 votes
37 votes
5 answers
3