There is a 4 digit card number,

4th digit is double of 1st digit,

2nd n 3rd digits are same,

And last digits together are double of first two digits

**Can you guess the car number?**

Check your answer:-

Click here to see Explanation

lets assume first digit is x, then the 4th digit will be 2x.

also assume 2nd and 3rd digits are y.

then from => last two digits are double of first two digits, we can say

also assume 2nd and 3rd digits are y.

then from => last two digits are double of first two digits, we can say

**y(2x) = 2*(xy)**We can rewrite is as 10y + 2x = 20x + 2 y 8y = 18x 4y = 9x; => y/x = 9/4 as x and y are integers y => 9, x => 4

thus the car number is **4998**

Facebook Comments

harsha says

Can 0000 be also an answer ? I think it holds good all conditions 🙂

Vedikuyil Azhagan says

how can you write last two digits with “y(2x)”?

sameer sakpal says

y is 3rd letter and 2x is 4th one… and as given in puzzle last 2 digit means y(2x)

Bhargavi says

how the 10c+d=2(10a+b) derrvied

DesertLady says

The puzzle asks for the “car” number and proceeds to lay out clues to come up with a 4-digit “card” number. No clues about a car, but a card number result could be 1002. 1002 works as well as 4998, so does 2004, 3006, 4008, and so on. Puzzle’s got too many typos.

Sean says

I think when they say (last two digits together, they mean concatenation, not sum. i.e. 49*2 = 98, not 2*(2+0) = (0+4)

Kurlee Locks says

Thanks.

naveen says

Let t number be ABCD

Now d= 2a

C=b

10c + d = 2(10a + b)