Alan, Bispah and Chan share a sum of money.
Alan gets
1
8

18
of the money.
Bispah gets
1
2

12
of the money.
Chan gets the rest of the money.
Alan gets £2.50
Find the ratio
amount of money Alan gets : amount of money Chan gets
Give your answer in the form
a
:
b
a:b
where
a
a
and
b
b
are whole numbers and the ratio is in it simplest form.