20增加10%后,再减少10%,结果是( ) A.20 B.19.8 C.20.2 D.18
问题描述:
20增加10%后,再减少10%,结果是( )
A. 20
B. 19.8
C. 20.2
D. 18
答
20×(1+10%)
=20×1.1
=22,
22×(1-10%)
=22×0.9
=19.8.
故选:B.