Help me please!

Question

When you reverse the digits in a certain two-digit number you decrease its value by 36. Find the numer if the sum of its digits is 12.

Answer 1

using algebra, let the number be ab

ab means 10a+b

reverse the digits to get ba

10b+a=10a+b-36

10b-b+a-10a=-36

9b-9a=-36

a+b=12

a=12-b

substitute

9b-9(12-b)=-36

9b-108+9b=-36

18b=108-36

18b=72

b=72/18=4

if b=4, then a=8

the number is 84

 

Answer 2

Hello, Susana

 

The numbers 48 and 84.  84-48= 36

 

How:  The two digit integers must add up to 12. So, they must be the following pairs.

3,9     They add up to 12.  So the numbers are 93 and 39. But  93-39: 57. So, these are not the numbers.

4,8     They add up to 12.  So the numbers are 84 and 48. 84-48= 36.  So, these should be the numbers

5,7     They add up to 12. So the numbers are 75 and 57.  75-57 =18. So the numbers don't work.

6,6 

 

I hope this helps you out a little and thanks for posting.

 

D.Y. Taylor

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