¾ of the seats in a concert hall were occupied. The ratio of adults to children was 7 : 3. If 90 more adults attended the concert, the number of adults would be 3 times the number of children. How many seats were in the concert hall?

Answer 1

in each 10, there are 7 adults, and three children

(A+90)=3C
but A/C=7/3 or A=7C/3

7C/3 + 90=3C
2/3 C=90
C=135
A=7/3 135=7(45)= you do it.

Finally, number of concert seats.
3/4 Seats= A+C solve for Seats

Answer 2

84