Question

Five hundred kids are going to Goa. The first bus will start when $40\%$ of the kids report at the bus station. If $180\;$ kids have arrived, the first bus will wait for how many kids to arrive?

Answer 1

Hint: The bus will start when $40\%$ kids report. So, first, find the number of students needed to report which is $40\%$ of $500\;$ kids. Given that already $180\;$ kids have arrived so to find how many more kids are needed for the bus to start, subtract $180\;$ from the number of students required for the bus to start.

Complete step-by-step solution:
The total number of students going on a trip to Goa is $500\;$.
Given that $180\;$ students have already arrived.
The first bus requires $40\%$ of the students to start.
To find the $40\%$ of total students we multiply the given percentage by the total number of students going to Goa.
$\Rightarrow 40\% \times 500$
The percentage symbol can be removed by multiplying with $\dfrac{1}{{100}}$
On substituting we get,
$\Rightarrow 40 \times \dfrac{1}{{100}} \times 500$
On further evaluation, we get on canceling $100\;$ times $5$ ,
$\Rightarrow 40 \times 5$
$\Rightarrow 200$
$200\;$ kids are required for the bus to start.
Given that $180\;$ kids have already arrived.
So to find more how many kids are required for the bus to start, We must subtract $180\;$ from $40\%$ of the total number of kids which is $200\;$ .
$\Rightarrow 200 - 180$
On subtracting we get,
$\Rightarrow 20$

$\therefore 20$ more kids are required for the bus to start given that $180\;$ kids have already arrived out the total number of kids which is $500\;$.

Note: The symbol of percentage $\%$ denotes that the constant is given out of $100\;$. Whenever percentages are given, we must always convert them into fractions and then solve them to make it easier to simplify. Whenever an answer should be written in percentage form just multiply it by a hundred. The constant in front of the percentage symbol can also be a fraction or a decimal.