Puzzling Age Problem
Sarah is twice as old as Tom. Four years ago, she was three times as old as Tom was then. How old is Tom now?
Word Problem
A bridge is built across a river. One quarter of the bridge is over the left bank of the river and one third of the bridge is over the right bank. The river is 120 m wide. How long is the bridge?
Let Tom's current age be x.
ReplyDeleteSince Sarah is twice as old as Tom, her current age is 2x.
Four years ago:
Tom’s age was x - 4.
Sarah’s age was 2x - 4.
According to the problem, four years ago, Sarah was three times as old as Tom:
2x - 4 = 3(x - 4)
Expanding the equation:
2x - 4 = 3x - 12
Subtract 2x from both sides:
-4 = x - 12
Add 12 to both sides:
x = 8
So, Tom is 8 years old.