Question

16. There are two examinations rooms a and b. If 10 students are sent from a to b, then the number of students in each room is the same. If 20 candidates are sent from b to a, then the number of students in a is double the number of students in b. The number of students in room a is:

Answer 1

Let number of candidates in room a be x and number of candidates in room b be y

Since 10 candidates in room a are sent to room b

Then, in room a= x-10 and in room b=y+10

Since that are equal so

x-10=y+10

x-10-10=x-20=y............ (1)

Since, 20 candidates in room b are sent to room a

Therefore,

Candidates in room a =x-10+20=x+10

Candidates in room b =y+10-20=y-10

Since , candidates in room a are double than in room b

Therefore,

x+10=2 (y-10)

x+10=2y-20

x+10+20=2y

x+30=2y

x+30=2 (x-20)................from (1)

x+30=2x-40

30+40=2x-x

70=x

Therefore number of candidates in room a are 70.

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