Algebra
posted by Anonymous .
Another bank offers a different savings rate. If an account with $400 earns interest of $6, how much interest is earned by an account with $1800?

Just use a simple ratio equation
x/6 = 1800/400
x = 27
or
rate for the account = 6/400 = .015
so for the $1800 , interest = .015(1800) = 27