Four brothers invested in a restaurant. one brother invested $140000. two brothers invested in the ratio x: 2x, and the fourth brother invested an amount equal to the three brothers combined. the total investment was $1600000. how much did each brother invest?

Hope its right. 

1. What you want to do is do is to know 2x is the ratio and x; $140,000 is the 1 brother investment and total is $1,600,000

2. Put them together 2x (140,000 + x + 2x) = 1600,000
3.                                   280,000 + 2x + 4x   = 1600,000
4.                                   280,000 +  6x          = 1600,000
5                                                   1600,000-280,000= 1320,000 /6
6. They each invested $220,000