Yucai Primary School has 140 people participating in three interest groups. It is known that half of the people in the art group, one third of the people in the calligraphy group and one quarter of the people in the calligraphy group.
Suppose the number of people in the calligraphy group is 12, then according to the meaning of the question, the number of people in the art group is 12/3*2=8, and the number of people in the sports group is 12/4*5= 15.
From the above analysis, we can know that the proportion of the three groups is: art group: calligraphy group: sports group = 8: 12: 15.
Use the solution ratio method to find the number of people in three groups as follows:
Art group =140 * 8/(8+12+15) = 32 (person)
Calligraphy group =140 *12/(8+12+15) = 48 (person)
Exercise group =140 *15/(8+12+15) = 60 (person)