Solution:
Let "x" be the total students in school
Given that,
Three sevenths of the students in a school are in sixth grade
Therefore,
[tex]\frac{3}{7} \times x = sixth grade[/tex]
sixty three of them are sixth graders
Therefore,
sixth grade students = 63
Therefore,
[tex]\frac{3}{7} \times x = 63\\\\x = 63 \times \frac{7}{3}\\\\x = 21 \times 7\\\\x = 147[/tex]
Thus there are 147 students in school
