Answer:
They will interfere to create a crest with an amplitude of 2.
Explanation:
The two waves will interfere and the resultant amplitude will be given by the principle of superposition, which states that the resultant amplitude is given by the sum (or the difference, if they meet in opposite phase) of the amplitudes of the two waves. In this case, the crest of wave C meets the through of wave D, so they are in opposite phase, therefore the resultant amplitude will be
A = A(C) - A(D) = 3 - 1 = 2
