The number of girls and boys in a class are in the ratio 7: 5 and there are 8 more girls 10 boys. how many girls and boys are there in the class.
number of girls ---- 7x
number of boys ---- 5x
"there are 8 more girls 10 boys" makes no sense
are you saying, "there are 8 more girls than boys" ?
which translated into math would be
7x = 5x+8
take it from here