1/4 of the number of people in calligraphy group is 1/5 of the number of people in sports group. Number of people in calligraphy group: number of people in sports group =4:5.
Number of people in art group: number of people in calligraphy group: number of people in sports group =8: 12: 15.
Number of people in the art group:140 ÷ (8+12+15) × 8 = 32.
Calligraphy group:140 ÷ (8+12+15) ×12 = 48 people.
Number of people in sports group:140 ÷ (8+12+15) ×15 = 60 people.