Question

There are n students in a school. If r % among the students are 12 years or younger, which of the following expressions represents the number of students who are older than 12?

Options

• nr/100

• n(1 – r)

• n(1 – r)/100

• n(100 – r)/100

Answer 1

n(100 – r)/100

Explanation:

Total number of students in a school = n

r % among the students in a school are of 12 years old or younger. The above equation represents that if r % students are 12 years old or younger, it means that (100 – r)% students are older than 12 years.

∴ (100 – r)% of n = `((100 - r)n)/100`