Form an equation to help you solve this problem. A school bus is full as it sets off. At the first stop 3 children get off and at the next stop a third
of the remaining children get off, leaving the bus only half full.
How many children were on the bus at the start?

  12

Step-by-step explanation:

If there are x children on the bus at the start, after the first stop, there are (x-3) remaining. After two stops, the number on the bus is ...

  x/2 = x -3 -(1/3)(x -3)

Multiplying by 6, we have ...

  3x = 6x -18 -2(x -3)

  3x = 4x -12 . . . . simplify

  12 = x . . . . . . . . add 12-3x

There were 12 children on the bus at the start.

Check

After 3 got off at the first stop, there were 12-3 = 9 remaining. 1/3 of those, or 9/3=3 got off at the second stop, so 9 -3 = 6 remained. This is half the original number, as required.

people went from manufacturing one object at a time by hand to manufacturing many objects in factories