Answer :
Sugita can do 1/4 part of a work in a day.
Her rate is;
[tex]\frac{1}{4}\text{work / day}[/tex]Ranju can do 1/3 part in 1 day;
His rate is;
[tex]\frac{1}{3}\text{work / day}[/tex]If they worked together for a day, they would do;
[tex]\begin{gathered} \frac{1}{4}+\frac{1}{3}=\frac{3+4}{12} \\ =\frac{7}{12}\text{work / day} \end{gathered}[/tex]Therefore, if they worked together, they would do 7/12 of the work in one day.