Irrigation - Engineering

Q1:

If d1 is the depth of cutting, d2 is the height of the bank from bed level r2 : 1 and r1 : 1 are the slopes in filling and cutting respectively, the horizontal distance n between the bed and bank, is

A x = r1 d1

B x = r2 d2

C x = d1 / r1

D x = d2 / r2

ANS:B - x = r2 d2

D2 is the depth from bank to bed level which is the same for both sides.
So, r2*d2 gives the horizontal distance between the bed and the bank directly.