in a particular city there are 100 homes numbered from 1 , 23 , . . , 100 . the city was build by a builder from chennai . there was 4 to 5 shops in the town which was build by a builder from mumbai . the 2 nd builder can build in 1 ½ times as compared to time by 1 st builder . the 2 nd builder builds in 15 days , then how many 2 ' s are used by the builder from chennai in numbering the 100 homes ?
Choose the correct choice from the following answers:
A) 17  B) 18  C) 19  D) 20  E) 21

Rationale: in the last line it should be given the builder from chennai in numbering the 100 homes ? then ans is 20 answer : d
Answer: D