Question

Megan is 5 years older than Sandy. If four years ago Megan was three years less than three times Sandys age, how old is Sandy now ?

Answer 1

Let the present age of Sandy be 'x' .

So, present age of Megan will be = x + 5

Therefore age of Sandy four years ago = x - 4
Age of Megan four years ago = x + 5 - 4 = x + 1


It is given that four years ago Megan was three years less than three times Sandys age.

So, an equation can be formed as follows;

$= > x + 1 = 3(x - 4) - 3 \\ \\ = > x + 1 = 3x - 12 - 3 \\ \\ = > 1 + 15 = 3x - x \\ \\ = > 2x = 16 \\ \\ = > x = 8$
Therefore the present age of Sandy is 8 years.

Answer 2

Sandy is currently 8 years old. 

Start by using x for Sandy's current age and x + 5 for Megan's current age. 

Since we know the above, we can find their age's as of 4 years ago as both of those minus 4. So Sandy 4 years ago was x - 4 years old and Megan was x + 1 years old. 

Now we can set up an equation that shows that Megan's age 4 years ago was equal to Sandy's age 4 years ago times 3 minus 3. 

x + 1 = 3(x - 4) - 3
x + 1 = 3x - 12 - 3
x + 1 = 3x - 15
x + 16 = 3x
16 = 2x
8 = x

Which is Sandy's current age.