$3.$ Consider the boring log shown in Figure $7\mathrm{.}30$ on pages $138139.$ Assuming that the SPT values $($given at the rightmost column in the boring$)$ are N

$60$

$$

values and using the information given in this chapter, compute the $($N

$1$

$$

$)$

$60$

$$

values at depths of $10$

$$

and $20$

$$

$.$