Question

Simpify the expression:
[12 ÷ 3 × 1] + 10 × 9 − 9 + [10 − 15 ÷ 5 + 3] × 3 ÷ 5

• A. 11
• B. 91
• C. 15

Answer 1

The correct option is B 91

The order of operations for solving a mathematical expression that we must follow is:
$P\to \text{Parenthesis}E\to \text{Exponents}M\to \text{Multiplication}D\to \text{Division}A\to \text{Addition}S\to \text{Subtraction}$

To simplify the given expression, let's proceed step by step according to the order of operations.

Also we know that when operations are at the same level, like multiplication and division or addition and subtraction, we move from the left to the right.

$[12÷3\times 1]+10\times 9-9+[10-15÷5+3]\times 3÷5$
Solving the terms in parenthesis
$=[4\times 1]+10\times 9-9+[10-15÷5+3]\times 3÷5$
$=4+10\times 9-9+[10-15÷5+3]\times 3÷5$
$=4+10\times 9-9+[10-3+3]\times 3÷5$
$=4+10\times 9-9+[7+3]\times 3÷5$
$=4+10\times 9-9+10\times 3÷5$
Solving the multiplication terms
$=4+90-9+10\times 3÷5$
$=4+90-9+30÷5$
Solving the division terms
$=4+90-9+6$
Soving the addition and the subtraction terms
$=94-9+6$
$=85+6$
$=91$