The task is to generate the correct answer for a given math problem.

[EX Q]: Problem: a certain kind of necklace is made from 9 green , 6 white , and 3 orange beads . what is the maximum number of these necklaces that can be made from 45 beads of each color ?
[EX A]: 5

[EX Q]: Problem: by selling an article for $ 225 a person gains $ 75 . what is the gain % ?
[EX A]: 50 %

[EX Q]: Problem: 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 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 ?
[EX A]:
20