13. Three mark exercise problems V

In a school excursion, $6$ teachers and $12$ students from $6^{th}$ standard and $9$ teachers and $27$ students from $7^{th}$ standard, $4$ teachers and $16$ students from $8^{th}$ standard took part. Which class has the least teacher to student ratio?

 

 

7th8th6th standard has the least teacher to student ratio.