Question

there are 420 girls and boys at a community centre.The ratio of girls and boys at the centre is 7to 3.How many girls are at the concert

Answer 1

g + b = 420 ;
g / b = 7 / 3 ;
Then, g = ( 7 / 3 )b;
( 7 / 3 )b + b = 420 ;
7b + 3b = 1260 ;
10b = 1260 ;
b = 126 ( boys );
g = ( 7 / 3 )× 126 = 294 ( girls ) ;