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68) https://www.meritnation.com/ask-answer/question/please-suggest-an-easy-and-fast-way-to-solve-this-the-sum/math/10001609
69) https://www.meritnation.com/ask-answer/question/the-length-of-longest-rod-that-can-be-placed-in-a-room-of/surface-areas-and-volumes/3396237
68) https://www.meritnation.com/ask-answer/question/please-suggest-an-easy-and-fast-way-to-solve-this-the-sum/math/10001609
69) https://www.meritnation.com/ask-answer/question/the-length-of-longest-rod-that-can-be-placed-in-a-room-of/surface-areas-and-volumes/3396237