A merchant Trade....?

Question

A merchant buys X number shorts each costs 45$.But when he checks the invoice given, there are 2 UNREADABLE digits on where he only can read _92_$

Its very well known that the number of shorts he bought are ODD NUMBERS.

Whats the total of the 2 UNREADABLE numbers?

Answer 1

Since the cost of the shorts is $45 each, the total would have to end in a 5 or a 0 (try and multiply 45 by different numbers. it will always end in 5 or 0). So, let's try some numbers:

1920 - nope
1925 - nope
2920 - nope
2925 - 65, yup, since 65 is odd

So, the unreadable numbers are 2 and 5.

Answer 2

Since the number of shorts purchased is an odd number, the last digit must be a 5 since each pair costs $45. Through trial and error you can determine which of the integers 1, 2, ..., 9 belongs in the first place because the resulting 4 digit number would have to be divisable by 45. It turns out the first digit has to be a 2 and therefore the sum of the unknown digits is 2 + 5 = 7.

Math Rules!

Answer 3

The last number must be 5 since any odd number multiplied by any nomber anding in 5 will have a product ending in 5, so we now have
$x925 since they are $45 each & 45*9*5, the answer must be divisible by 9. Therefore x+9+2+5 must be divisible by 9
9+2+5=16 so x must be 2. 2+9+2+5=18
$2925/$45=65 pair of shorts.

Answer 4

Since 45 contains a factor of 5, the last digit of 45x is either 0 or 5. Since x is odd, the last digit is 5.

So 45x = _925. We could do some clever long division argument to solve for the digit, or we could just guess and check because there are only 10 possibilities, and notice that 2925 is divisible by 45.

Answer 5

2925$