Question

Which number is the odd one out - 515, 428, 339, 224, 236, 199, 645?

Answer 1

Ans : 645

Below is the explanation,

515, 428, 339, 224, 236, 199, 645

(First digit * Second digit) = Third digit.
Apply this formula for all the above number.
(515) ===> 5 * 1 = 5
(428) ===> 4 * 2 = 8
(339) ===> 3 * 3 = 9
(224) ===> 2 * 2 = 4
(236) ===> 2 * 3 = 6
(199) ===> 1 * 9 = 9
(645) ===> 6 * 4 = 24 (This is the odd one)

Answer 2

The ODD number is 224

As it is the only number divisible by 7, else are not.