Order doesn't mater so use combinations:
6C3 = 6!/ (3! (6-3)! ) = 6! /(3!*3!) = 6*5*4*3! / (3! 3!) = 6*5*4/3*2*1) = 20
51 = 3 * 17, sum of 20, no good.
<span>52 = 2 * 2 * 13, sum of 17, no good. </span>
<span>54 = 2 * 3 * 3 *3, sum of 11. </span>
<span>The answer is 54. If you need more help, let me know.</span>
It’s probably 10 given proof
