The ratio of the number of adults to the number of students at the school dance has to be 1:10. Last year there were 477 more students than adults at the dance. If the school is expecting the same attendance this year, how many adults have to attend the dance?
Let number of adults attending the dance = a
Let number of students attending the dance = s
a/s = 1/10 ....multiply both the sides by 10 s
s = 10a ........(1)
There were 477 more students than adults
s = a + 477 ........(2)
Substitute (2) into (1)
a + 477 = 10a ....subtract a from both the sides
477 = 9a .....divide both sides by 9
53 = a
So 53 adults have to attend the dance.