Given : Two groups
Group A: contains 390 people.
Three fifths of the people in group A will be selected to win $100 fuel cards.
So, the number of people who will win = 3/5 * 390 = 234
Group B : contains 553 people
the group will receive the same number of fuel cards
so, the group will receive 234 cards
The non-winners of group A = 390 - 234 = 156
The non-winners of group B = 553 - 234 = 319
The ratio between them = 156 : 319