What is the number?
A number is increased by 3, then multiplied by 4. The result is the same as if the number had first been multiplied by 4 and then increased by 24.
What is the number?
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 the number be x.
ReplyDeleteFirst method (increase, then multiply):
Increase by 3 → x + 3
Multiply by 4 → 4(x + 3)
Second method (multiply, then increase):
Multiply by 4 → 4x
Increase by 24 → 4x + 24
We are told these are equal:
4(x + 3) = 4x + 24
Expand the left-hand side:
4x + 12 = 4x + 24
Subtract 4x from both sides:
12 = 24
Uh-oh — this is not true.
There is no number that satisfies this condition.
ReplyDeleteThis is one of those sneaky 11 Plus questions where the algebra shows the situation is impossible.