Question

Thirty minutes before a concert, there were 1,200 people in the 3,000-seat auditorium where the concert was being held. Five minutes before the concert, the auditorium was 90% full. Which of these equations can be used to determine p, the number of people who entered the auditorium during this time interval?

Answer 1

Answer: p = 1500

Explanation:

Initially, there were 1200 people.

After the given interval, we know that the auditorium is 90% full (where the auditorium can hold a maximum of 3000 people)

Then after the interval, the number of people in the auditorium is equal to the 90% of 3000.

When we have a percentage X of a quantity A, the quantity of the percentage X is:

N = (X/100%)*A

In this case, the 90% of 3000 is equal to:

N = (90%/100%)*3000 = 0.9*3000 = 2700.

Then, at the beginning of the interval there were 1200 people, and at the end there were 2700.

The difference is:

p = 2700 - 1200 = 1500

This means that the number of people who entered the auditorium dirung the time interval is 1500.