With the start of school approaching, a store is planning on having a sale on school materials. they have 600 notebooks, 500 folders and 400 pens in stock, and they plan on packing it in two different forms. in the first package, there will be 2 notebooks, 1 folder and 2 pens, and in the second one, 3 notebooks, 1 folder and 1 pen. the price of each package will be $6.50 and $7.00 respectively. how many packages should they put together of each type to obtain the maximum benefit?