Pattern's pattern

Here’s a puz­zle to test your abil­ity to find a pat­tern and test it against more data.

In this table, each row across fol­lows the same pat­tern of num­bers. See if you can dis­cern the pat­tern and fill in the miss­ing num­ber in the bot­tom row. For added chal­lenge (or com­pe­ti­tion), time how long it takes you to com­plete the puz­zle. Then, pass it along to some­one else and see if they can solve it faster. The slower one has to cook din­ner!

7	4	8
3	9	7
6	5	10
?	8	4

Have you solved it yet? If not, here’s a hint:

If you read your fig­ures like words in the West,
then mul­ti­ply your efforts and sub­tract the rest.

Keep read­ing for the answer and solu­tion.

(7x4)-8 = 20

(3x9)-7 = 20

(3x8)-4 = 20

The answer is 3.