निम्नलिखित में से कौन सी संख्या अन्य तीन से भिन्न है: 121, 144, 169, 198?

Find the odd one out among the given numbers: 49, 121, 169, 225.

Three of the following four number-pairs are alike in a certain way and one is different. Select the number-pair that is different.

Four numbers are given below, in which three of them follow the same logic. Find the different number.