#### A jet travels at 610 mi/hr relative to the air. it takes the jet 1.6h longer to travle the 3660 mi from London to Washington DC against the wind than it takes from Washington to London with the wind. find the velocity of the wind?

$Lets\;say\;velocity\;of\;wind=V\;and,\\*with\;the\;wind\;jet\;takes\;T\;hrs.\\* then\;against\;the\;wind\;it\;will\;take\;(T+1.6)\;hrs.\\*Also\;with\;the\;wind\; equivalent\;velocity=(610 + V)\;miles/hr\;and,\\*against\;the\;wind\; equivalent\;velocity=(610-V)\;miles/hr\\* So,\\*(610+V)\times(T)=3660\;\;\;\; \;\;\;\;\;\;\;\;\;..eq(1),\\*(610-V)\times(T+1.6)=3660\;\;\;\;..eq(2)\\* From\; eq(1)\;and\;eq(2)\;we\;get,\\* VT=488-0.8V\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;..eq(3)\\* Put\;VT\;from\;eq(3)\;in\;eq(1),we\;get,\\* 305T=1586+0.4V\;\;\;\;\;\;\;..eq(4) \\*Now,\;multiply\;eq(1)\;by\;305\;and\;put\;value\;of\;305T\;from\;eq(4),we\;get\\* (610+V)(1586+0.4V)=305\times3660 \\*We\;got\;quadratic\;in\;V,\; solve\;it\;to\;get\;V\\* 0.4V^2+1830V-150670=0\\* we\;will\;get\;\\* V=83.87\;miles/hr$