已知:2+23=22×23,3+38=32×38,4+415=42×415…,若10+ab=102×ab(a、b为正整数),则a+b的值为(  ) A.89 B.91 C.109 D.111

问题描述:

已知:2+

2
3
=22×
2
3
,3+
3
8
=32×
3
8
,4+
4
15
=42×
4
15
…,若10+
a
b
=102×
a
b
(a、b为正整数),则a+b的值为(  )
A. 89
B. 91
C. 109
D. 111

∵2+

2
3
=22×
2
3
,3+
3
8
=32×
3
8
,4+
4
15
=42×
4
15
…,10+
a
b
=102×
a
b

∴a=10,b=102-1=99,
∴a+b=10+99=109.
故选C.