Given: →u=5^j m/s
Acceleration, →a=10^i+4^j and final coordinates (20, y0) in time t.
Using equation of motion along x-axis,
x=uxt+12axt2
[∵ux=0]
⇒20=0+12×10×t2
⇒t=2 s
Using equation of motion along y-axis,
y=uy×t+12ayt2
y=y0=5×2+12×4×22=18 m
Hence, (A) is the correct answer.