if a is divisible by 2, b is divisible by 5 and a/b=7/9, where a and b are positive numbers, and a+b<400, what is one possible value of a + b?

ok im not sure how to set this up...i would try to do this one by plug and chug.

i would try to find a number that was even and one that was odd whose sum would be less then 400.

so i dunno, one number has to be divisible by 5? let that number be 60 and the other number has to be divisible by 2 so it would be 330?

ok but a/b has to be 7/9 so whatever value i selected for a or b i would substitute and then solve.

so i would keep playing with the number until i got something that worked. my problem is time, i dont have time to plug and chug. so is there a faster way i can do this problem