Greg bought three comic books on sale. The total cost of his purchase with 8% sales tax is given by the expression 3b + 0.08 (3b), where b is the price of one book. If b = $3.50, how much did Greg pay all together? $7.02 $11.34 $13.02 $111.09

The amount Greg paid all together is $11.34.

Step-by-step explanation:

Here, the total cost expression is given as

C (b) = 3b + 0.08 (3b)

Now, given b = $3.50.

Substituting the value of b in the cost expression,

So, the cost value = 3 ($3.50) + 0.08 (3) ($3.50)

= 10.5 + 0.84 = 10.78

or, C = $11.34

Hence, the amount Greg paid all together is $11.34.