Question

Each row has “$a$” children’s fantasy books and “$b$” non-fantasy books. Choose the incorrect statement regarding the number of items in 5 rows.

• A. The algebraic expression representing the number of items is $5a+5b$.
• B. The coefficient of the algebraic expression is $5$.
• C. The variables in the algebraic expression are “$a$” and “$b$”.
• D. The algebraic expression representing the situation is $25ab$.

Answer 1

The correct option is D The algebraic expression representing the situation is $25ab$.

Number of children’s fantasy books in each row $=a$
Number of non-fantasy books in each row $=b$

The number of children’s fantasy books in $5$ rows $=5\times a=5a$
The number of non-fantasy books in 5 rows $=5\times b=5b$

The number of items in the 5 rows $=5a+5b$ (these cannot be added as these are unlike terms.)

Algebraic expression: $5a+5b$
$\text{Terms}$	$5a$	$5b$
$\text{Coefficient}$	5	5
$\text{Variables}$	$a$	$b$

The algebraic expression representing the number of items is $5a+5b$. So, Option A is correct.
The variables in the algebraic expression $5a+5b$ are “$a$” and “$b$” respectively. So, Option B is correct.
The coefficient of “$a$” and “$b$” both in the algebraic expression is 5. So, Option D is also correct.

Option C is the incorrect choice.