Question 1154755
<br>
If Landon is three times as old as his little brother, then the difference between their ages is twice the age of his little brother.<br>
(Algebraically, the difference between 3x and x is 2x.)<br>
We are told that difference in their ages is 10 years.<br>
So 10 years is twice his little brother's age; so his little brother is 5.<br>
And that makes Landon 15.<br>