Given √224_r = 13_r the value of radix r is
(A) 10
(B) 8
(C) 6
(D) 5


Answer: (D)

Explanation:

√224r = 13r
taking square both sides

2r2 + 2r + 4 = r2 + 6r + 9
= r2 - 4r - 5 = 0
= (r - 5)(r + 1) = 0
r = 5 // since it can\'t be -1

So, option (D) is correct.

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