word problem

IMO, The problem's language is not structured very well.

The problem should have been worded like this:
Jessi has an investment portfolio of stocks and bonds.
If she buys 6 more stocks, she will have twice stocks as bonds.Triple the number of bonds, she would have 3 less than twice the number of stocks. If she sells half her stocks, how many stocks and bonds will she have?

S + 6 = 2B -- (1)
3B = 2S - 3 -- (2)

Using the two equations above,
4B - 12 = 3B + 3
B = 15
S = 24

If she sells half of her stocks, 12 stocks will remain.
So, she will have 12 + 15 = 27 number of stocks and bonds.