A motorcycle licence plate has two letters followed by four numbers. How many plates can be made without duplicating? ( there are no plates with number zero)

Please give the full solution.

Dear Student!!!

@ Navin: Good work..!! Keep it up. 

You have covered only one case (in which answer should be 6759324).

There can be two cases as follows:

Case 1: When letters are repeating

No. of ways of selecting of selecting number plates (including XX 0000) = 6760000 

No. of ways of selecting plate with zero number= 26 × 26 × 1 = 676 

Required no. of ways = 6760000 – 676 = 6759324

 

Case 2: When letters are distinct

 26  25  10 10 10 10

 (letters)  (numbers)

No. of ways of selecting letters = 26 × 25 = 650

No. of ways of selecting numbers = 10 × 10 × 10 × 10 = 10000

No. of ways of selecting of selecting number plates (including XX 0000) = 650 × 10000

   = 6500000

No. of ways of selecting plate with zero number = 26 × 25 × 1 = 250

Required no. of ways = 6500000 – 250 = 6499750

 

Cheers..!

  • 6

I assume it means no plate can have "xx0000" but it can have "xx0473" or " xx0001"  right?

On that asumption, the number of the plate can be formed when ist letter is selected and then2nd and then ist numeric digit , then 2nd, then 3rd and then 4th numeric digit are selected.

Ist letter can be selected in 26 ways, second letter also in 26 ways (as it is not mentioned that alphabets should be different), Ist numeric  in 10 ways (i.e. any of the 10 digits), 2nd numeric also 10 ways, 3rd numeric also 10 ways and 4th also 10 ways so total ways will be 26 * 26 * 10*10*10*10 = 5760000 ways. But these include numerics 0000 also which will be 26*26*1 ways = 576 ways (ist letter 26 ways, 2nd letter 26 ways and then 4 digits 0000 in one way so total 26*26*1 ways)

So total no of plates = 5760000 - 576 = 5759424 ways

-navinsaxena.del@gmail.com

  • 6

sorry there was a calculation mistake 26 826 = 676 , (i have wrongly taken as 576) but the method is same, u may rectify calculations.

  • 1

I assume it means no plate can have "xx0000" but it can have "xx0473" or " xx0001"  right?

On that asumption, the number of the plate can be formed when ist letter is selected and then2nd and then ist numeric digit , then 2nd, then 3rd and then 4th numeric digit are selected.

Ist letter can be selected in 26 ways, second letter also in 26 ways (as it is not mentioned that alphabets should be different), Ist numeric  in 10 ways (i.e. any of the 10 digits), 2nd numeric also 10 ways, 3rd numeric also 10 ways and 4th also 10 ways so total ways will be 26 * 26 * 10*10*10*10 = 6760000 ways. But these include numerics 0000 also which will be 26*26*1 ways = 676 ways (ist letter 26 ways, 2nd letter 26 ways and then 4 digits 0000 in one way so total 26*26*1 ways)

So total no of plates = 6760000 - 676 = 6759524 ways

  • 23

yeah rite !

But as the question does not mention about distinct letters, i asumed it as repeatition case only.

Thanks ! -Navin

  • 0
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