On a bus, there were 3/5 as many children as adults. At the first stop, 15 adults boarded the bus. At the second stop, 40 adults alighted from the bus, and the number of children became 2/3 of the number of adults. How many children were there on the bus?
Let the number of adults be x
number of children =3/5x
Total number of adults at the first stop=x+15
Remaining number of adults at the second stop =(x+15)-40 =x-25
Number of children at the second stop =2/3(x-25) =2/3x-50/3
Number of children neither increased nor decreased
therefore, 3/5x= 2/3x-50/3 (multiply each fraction by 15 which is the LCM of 5, 3 and 3)
9x=10x-250
9x-10x=-250
-x=-250
x=250
Therefore, initial number of adults was 250
thus, number of children =3/5 of 250
=150 children