How many adults have to attend the prom?

Question

The ratio of the number of adults to the number of students at the prom has to be 1:10. Last year there were 477 more students than adults at the prom. If the school is expecting the same attendance this year, how many adults have to attend the prom?

Answer 1

There's 1 adult for every 10 students.

That means there's 1 adult, 1 student, and 9 students.

If there were 477 more students than adults at the last prom, the 477 more students comes from the 9 additional students (1 adult, 1 student, 9 students).

477 / 9 = 53

Starting with a ratio of 1 adult and 10 students, multiply both numbers by 53 giving us:

53 adults and 530 students

Check to make sure:  530 - 53 = 477.  So there were 477 more students than adults last year.

Answer:  53 adults