A health survey recorded the number of times per week people exercise, categorized by age group.
| Age Group / Exercise per week | 0-1 | 2-4 | 5+ | Total |
|---|---|---|---|---|
| 18-30 | 15 | 40 | 25 | 80 |
| 31-50 | 20 | 30 | 10 | 60 |
| Total | 35 | 70 | 35 | 140 |
What fraction of the people in the 18-30 age group exercise 2-4 times per week?
