An investment firm recommends that a client invest in bonds rated AAA, A$,$ and B The average yield on AAA bonds is $5\%$ on A Bonds $7\%$ and on b bonds $12\%$ the client wants to invest twice as much in AAA bonds as in b bonds How much should be invested in each type of Bond if the total investment is $$19000$ and the investor wants an equal return of $$1370$ on the three investments

The client should invest how much in AAA bonds how much in A bonds and how much in b bonds