math question

[tofulover]

<p>10 Real SAT, the Redbook. Test 1, section 3, question 22:</p>

<p>AB
+BA</p>

<hr>

<p>CD4</p>

<p>In the addition problem above, each letter represents a different nonzero digit. What is one possible value of the 2 digit number AB??</p>

<p>I understand why the answer is 68 or 86 (that's the correct answer). but i DO NOT UNDERSTAND why AB cannot be either 95 or 59 because 95+ 59 also equals a 3 digit number that ends with a 4.</p>

[optimizerdad]

<p>...because 95 + 59 = 154, and 5 is one of the (A,B) digits.</p>

<p>The answer would be CA4 or CB4, <em>not</em> CD4 ; neither C nor D can equal A or B.</p>

[tofulover]

<p>thanx a bunch!!!!!</p>