My 100 followers question

Two small stones $A ,B$ of masses $1~kg$ and $2~kg$ respectively, are projected simultaneously at $t=0$. The stone $A$ is projected horizontally with speed $V_a~ms^{-1}$ from the top of a tower that is $Y$ meters high and the stone $B$ is projected from the ground at a distance $X$ meters from the foot of the tower with speed $V_b~=~90~ms^{-1}$ at an angle of $37^o$ with the horizontal as shown in the figure. At time $t~=~6~sec$ after projection, they collide in air and at that moment their velocities are mutually perpendicular. Then find $X~+~Y~+~V_a$

Note: give the sum of the numerical values of $X, Y , V_a$.