gracie
The palindrome 939 is the sum of three lesser palindromes. If the three have different lengths and use only the same two positive integers,
which is the sum of these two integers?
A. 8
B. 9
C. 10
D. 11
E. 12
firstly I take it that
use only the same two positive integers, means
use any one or both of same two positive integersa logical and fast approach could be -
the SUM is 939 and the other two palindrome will sum up lesser than 100+10 that is <110
so the biggest palindrome is \(> 939-110\) or \(>829\) and therefore the hundreds digit will be 8 or 9
lets check with 8..units digit of sum is 9, and that will be possible when two palindromes have 8 as units digit and third will become X9-2*8=X9-16=_3
so other digit will be 3
1) max possible sum = \(888+88+3 =979\neq{939}\)
2) other possibility = \(888+33+8 =929\neq{939}\)
so 8 is not the digit
Now let's check with 9..units digit of sum is 9, and that will be possible when all three are ODD units digit or when two digits are even and the third is 9
But he biggest is 9X9, which is <939 so X<3,
possible values 0, 1 and 2a)when two palindromes have 0 as units digit and third will become 9.. but then we will not have 2-digit number
b) when two palindromes have 9 as units digit and third will become X9-2*9=X9-18=_1..
so other digit will be 1
possibility = \(919+11+9 =939=939\)
so the digits are 9 and 1, sum = 1+9=10
C