In the given data,
No. of terms (N) = 35
Here,
Third quartile (Q3) = The value of \(\frac{3N^{th}}4\) item
= the value of \(\frac{(3\times35)^{th}}4\) item
= the value of 26.25th item
Here, CF just greater than 26.25 is 28 and it lies in the class ( 60- 80 )
Therefore, Third quartile class (Q3) = (60 - 80).