问题如下：
5. If Motelli’s current investment account of €250,000, has a cost basis of €175,000, and is invested in an investment which is expected to earn a return of 7.5 percent, all of which are deferred capital gains, what is his expected after tax accumulation in 15 years?
选项：
A.€673,247.
B.€683,247
C.€690,747.
解释：
B is correct.
The after tax wealth accumulation for deferred capital gains is
FVIFcg = (1 + r)n(1–tcg) + tcg–(1–B)tcg
FVIFcg = €250,000×[(1+0.075)15(1–0.1)+0.1–(1–0.70)(0.10)] =€683,247
请问为什么是用10%的税率？
