Question

Cole’s age is $3$ years less than his sister Tina’s age, $t$. If Cole is $18$, which equation represents this situation, and how old is Tina?

• A. The equation that represents this situation is $t-3=18$. Tina is $21$.
• B. The equation that represents this situation is $t+3=18$. Tina is $15$.
• C. The equation that represents this situation is $3-t=18$. Tina is $21$.
• D. The equation that represents this situation is $-3-t=18$. Tina is $15$.

Answer 1

The correct option is A

The equation that represents this situation is $t-3=18$. Tina is $21$.

The explanation for the correct option:

Option A:

• It is given in the question, Tina's age is $t$.
• Cole's age is $3$ year less than Tina's age, that is $t-3$.
• It is given that Cole's age is given to be$18$.

From the given question:

$t-3=18$

Adding $3$ both sides in order to solve for $t$:

$\begin{array}{rcl}t& =& 18+3\\ & =& 21\mathrm{years}\end{array}$

Therefore, the equation to find the age of Tina is $t-3=18$ and the age of Tina is $21$ years.

Hence, Option (A) is the correct option.