There were boys and girls in a field and hall.they then changed place and the number also changes

Question

There were 1000 students at the field and the hall.2/5 of the students at the field were girls.3/5 of the students at the hall were girls.After some students in both venues moved from one venue to another,3/10 of the students in the field and 7/10 of the students at the hall were girls.If there were 600 students in the field at first,how many students were there in the hall at first?

Answer 1

 

 

 At the beginning:

  600 students at the field. Then 1000 - 600 = 400 students in the hall.

  2/5 of the students  at the field were girls, so 2/5 * 600 = 240 girls at the field

  So 600 - 240 =360 boys were at the field.

 

  3/5 of the students in the hall were girls: 3/5*400 = 240 girls in the hall.

  So 400 - 240 = 160 boys in the hall.

 

 

  The following table summarizes the data at the beginning:

 

                             FIELD             HALL          TOTALS

    BOYS                  360                  160             520

 

    GIRLS                 240                  240             480

 

   TOTALS               600                   400             1000

 

 

 

There were 400 students in the hall.

 

The question does not ask anything about the 

number of students AFTER they moved, nor is

there any data given.