BTGmoderatorLU wrote:Source: Manhattan Prep
A palindrome is a number that reads the same forward and backward, such as 121. How many odd, 4-digit numbers are palindromes?
A. 40
B. 45
C. 50
D. 90
E. 2500
Number of options for the units digit = 5. (1, 3, 5, 7, or 9.)
Number of options for the thousands digit = 1. (Must be the same as the units digit.)
Number of options for the hundreds digit = 10. (Any of the digits 0-9.)
Number of options for the tens digit = 1. (Must be the same as the hundreds digit.)
To combine these options, we multiply:
5*1*10*1 = 50.
The correct answer is
C.
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