Question

From September 1991 to September 1994 the enrollment at a particular school declined by 20 percent. If the number of students enrolled at that school in September 1994 was 720, what was the enrollment in September 1991

Answer 1

900

Explanation:

Given that :

Enrollment declined by 20% from between September 1991 to September 1994

This means there was a reduction in enrollment ;

Enrollment in September 1994 = 720

Enrollment in September 1991 = x

Hence,

Enrollment in 1994 = (1 - decline rate ) * enrollment in 1991

720 = (1 - 20%) * x

720 = (1 - 0.2) * x

720 = 0.8x

720 / 0.8 = 0.8x/0.8

900 = x

Hence, Enrollment in September 1991 = 900 enrollments