I REALY NEEED HELP PLEASE HELP ME?

stu has twice as much as money invested in stocks as in bonds. stocks earn 8 PERCENT INTREST PER YER AND BONDS 2% PER YEAR. IF STU EARNED A TOTAL OF $400 DOLLARS FROM HIS STOCK AND BONDS LAST YEAR HOW MUCH MONEY DID HE HAVE INVESTED IN STOCKS?