Let speed of boat in still water = $$x$$ km/hr and speed of current = $$y$$ km/hr According to ques, => $$frac{16}{x+y}+frac{14}{x-y}=9$$ ----------------(i) and $$frac{40}{x+y}+frac{12}{x-y}=11$$ ----------------(ii) Applying the operation : $$5 imes(i)-2 imes(ii)$$ => $$frac{70}{x-y}-frac{24}{x-y}=45-22$$ => $$frac{46}{x-y}=23$$ => $$x-y=frac{46}{3}=2$$ --------------(iii) Substituting it in equation (i), => $$frac{16}{x+y}+frac{14}{2}=9$$ => $$frac{16}{x+y}=9-7=2$$ => $$x+y=frac{16}{2}=8$$ ------------(iv) Now, adding equations (iii) and (iv), we get : => $$2x=2+8=10$$ => $$x=frac{10}{2}=5$$ => Ans - (A)