Problem Solving

In a figure of xy plane, where point P (0,30) is on y axis, and point Q (50,0) is on X axis. How many of the points on line
segment PQ have coordinates that are both integers?

(A) 5
(B) 8
(C) 10
(D) 11
(E) 20

ans :'d'
wld appreciate explaination .