The length of inclined plane is 15 m. A stone is projected with speed v0 from point A to cross through point B. If minimum value of v0 is 3x ms-1. The value of x is _______.

For minimum value of v0 the maximum range on inclined plane should be AB - 15m. The maximum range will be Rmax=v02g1+sin⁡30∘ Or     v02=15×10×32    v02=152∴    v0=15ms−1=3x∴    x=5