Question

There were 30 elephants in a jungle. Some decided to move into the city to entertain children at a fair. The head elephant announced that 19 of them should remain back in the jungle. What is the equation that will help us to find the number of elephants who went to the fair?

• A. $x-30=19$
• B. $30-x=19$
• C. $x-19=30$

Answer 1

The correct option is B $30-x=19$

Let '$x$' be the number of elephants who went to the fair.

There were 30 elephants in total. Among these elephants, '$x$' number of elephants went to the fair.

Hence, the remaining number of elephants would be $30-x$.

We know that the remaining number of elephants who did not visit the fair is 19.
$\therefore$ The required equation is $30-x=19$

We assume that the number of elephants who went to the elephant, i.e., $x=10$.

By substituting the value of 10 in the above equation we check the validity of the assumption.
$30-x=19$
$\Rightarrow 30-10=19$
$\Rightarrow 20\ne 19$
$\Rightarrow \text{Left hand side}\ne \text{Right hand side}$

Hence, the assumption $x=10$ is not correct.