2. Suppose: a in the first quarter, (1+x%)a in the second quarter and (1+x %)A in the third quarter? What is the increase of A∴ (1+x%)?

3:200( 1+x)？ = 1000

4: A ( 1-0.2)？ = 0.64b0.6c (1-0.3) × (1-0.4) = 0.42 ∴ C.