Predict the Bomb's Landing Point!
JavaScript, 29 28 bytes

Thanks @user5090812 for golfing off 1 byte



(a,b,x,y)=&gt;a+x*((b+y-1)/y|0)


Try it online!

If it did not have to move x then y but was instead falling in a straight line it would be 18 bytes

(a,b,x,y)=&gt;a+x*b/y