5/7 students are boys. There are 18 more boys than girls. How many altogther in the group?

Let the number of boys be B and the number of girls be
G.

There are 18 more boys than
girls.

Then, B = G + 18
...............(1)

Also, given that 5/7 of the students are
boys.

==> (5/7)* (B+G) =
B............(2)

We will substitute (1) into
(2).

==> (5/7) * (G+18 + G) =
G+18

==> (5/7) *(2G+18)=
G+18

==> Multiply by
7.

==> 10G + 90= 7G +
126

We will combine like
terms.

==> 3G =
36

==> G =
12

==> B = 18+12 =
30

==> G + B = 30+12 =
42

Then there are 42 girls and boys in the
group.