Answer:
Here, b represents buying fins and leashes.
As per the statement:
Vincent is ordering accessories for his surfboard. A set of fins cost $24 each and a leash costs $15.
A set of fins cost $24 each and a leash costs $15
⇒ Cost of total fins = 24 b and Cost of total leashes = 15 b
It is also given that: The shipping cost is $4 per order.
then;
Cost in dollars of buying b fins and b leashes plus the cost of shipping
= 
Therefore, the expression
represents the cost in dollars of buying b fins and b leashes plus the cost of shipping.
10
(a)
True.
The given terms in the expressions are 24b, 10b and 4
(b)
True.
Like terms are those which have same variable.
Like terms in the given expression are: 24 b and 15 b
(c)
False.
Combine like terms in the given expression:

Therefore, the simplified given expression is, 