car number plate-IAS
A car has number of 4 digits.
-4th digit is double of 1st digit
-2nd and 3rd digits are same.
-And last two digits are double of first two digits hai.
What is the car's number
Its Question Of Last IAS Exam ....
Lets see how many ppl can solve it
The answer is 4998.
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1 solution
Let the car's number plate be ABCD.
Then, D = 2A ; B = C ; 10C + D = 2 ( 10A + B )
On solving the last equality along with the previous two facts, we obtain 4C = 9A Now, since the digits have to be whole , the equality has to be equal to a whole number. Only non zero numbers satisfying are ( 9,4). Note that (0,0) shall lead to a trivial solution.
Hence ABCD = 4998