Let b sapling be x tree; Then, buy (600-x) seedlings; (600-x)* 88%+x * 96% & gt； =600*90%;

Namely: x96+(600-x) 88 >: = 90 * 600; (96-88)x & gt； =600*(90-88); X>= 150 trees.

450 * 60+150 * 80 = 27000+12000 = 39000 (yuan) < 44000 yuan; I have enough money with me.