in a class of 80 students every student studied economic or geography or both If 65students study economic and 50students study geography how many students study both subjects​

whats the question?

step-by-step explanation:

step-by-step explanation:

let pq = qr = rs = x, and xz = y and zu = z.

if the horizontal lines are parallel, then corresponding segments are in proportion:

substitute:

therefore 3 = y = z.

xu = y + z → xu = 3 + 3 = 6