The parameters a, b, c and d for the group index computation are obtained as 23, 28, 10 and 12 respectively. The CVPD is found to be 450. Find the thickness of the surface and base of the pavement for the above details.

The parameters a, b, c and d for the group index computation are obtai

1.	The parameters a, b, c and d for the group index computation are obtained as 23, 28, 10 and 12 respectively. The CVPD is found to be 450. Find the thickness of the surface and base of the pavement for the above details.
A.	29 cm
B.	39 cm
C.	30 cm
D.	20 cm
Answer» D. 20 cm