Question

Some children sat for a selection test for a direct school admission. There were 15 more boys than girls in the group. 3/4 of the girls and 4/5 of the boys passed the test. There were 2 more girls than boys who failed the test. How many children say for the selection test?

Answer 1

so, what have they told you?
1/4 girls and 1/5 boys failed, and so
b = g+15
1/4 g = 1/5 b + 2
solve for b and g.
now you want b+g