Cambridge University Admission Interview Tricks | Find x+y=?

[@raghvendrasingh1289]

Let x+y = t then x - y = 40/t we know that (x+y)^2 - (x - y)^2 = 4 xy t^2 - 1600/(t^2) = 396 t^4 - 396t^2 - 1600 = 0 (t^2 - 400)(t^2+4) = 0 t = 20 , -20 , 2 i , -2 i

[@hariomdas270]

X^2-Y^2=40 X (X-Y)(X+Y) =40 40=2*20,4*10,5*8, (1)2*20 X-Y=2,----------(1) X+Y=20--------(2) ADD(1)+(2) 2X=22 X=11 EQUETION (1) MINUS EQ(2) X+Y-X+Y=20-2 2Y=18 Y=9 ANSWER X=11 Y=9 X^2-Y^2=11^2-9^2=121-81=40 X.Y=11*9=99

[@hafeezrehman8692]

Value of X and Y?

[@9허공]

problem is x + y not (x, y)

[@Radioayandeh]

No need to calculation, x=11 & y=9