Question

There were 3 times as many boys as girls in a museum. After 75 boys left and 25 girls entered, there were 2 times as many girls as boys. If 90 children remained, how many children were in the museum at first? *

Answer 1

3x=y

3x-y=0

(y-75)+(X+25)=90

X+y=90+50

X+y=140

3x-y+X+y=0+140

4x=140

X=35(girls)

y=105(boys)

children were in the museum at first? *=35+105

=140