21 boys and 13 girls can finish a job in 1 day While 9 boys and 18 girls finish the same job in same time. Then, In how many days 3 girls can finish the job ?
1
\(5\frac{1}{4}\) days
2
\(6\frac{1}{4}\) days
3
\(4\frac{1}{4}\) days
4
\(8\frac{1}{4}\) days
5
\(7\frac{1}{4}\) days