number puzzle: Write your phone number. Multiply by...

[mmatlas]

I have the following question that I have solved. Just having difficulty trying to figure out why it works:

Write your phone number. Multiply that value by 2. Add 5. Multiply the sum by 50. Add your age to the product. Add 365 to the new sum. Subtract 615 from this sum. The result will be your phone nmber and age, with your age being in the ones and tens place. Use variables to show how this problem works.

I'm thinking that the multiply the sum by 50 is the key to this problem, but can't put my finger on it... HELP!

 

[Loren]

Write your phone number. Multiply that value by 2. Add 5. Multiply the sum by 50. Add your age to the product. Add 365 to the new sum. Subtract 615 from this sum. The result will be your phone nmber and age, with your age being in the ones and tens place. Use variables to show how this problem works.

Let your phone number be x and your age be y.

Write your phone number.... x

Multiply that value by 2.... 2x

Add 5.... 2x+5

Multiply the sum by 50.... 50(2x+5) = 100x +250

Add your age to the product.... 100x+250+y

Add 365 to the new sum.... 100x+250+y+365 = 100x+y+615

Subtract 615 from this sum.... 100x+y+615-615 = 100x+y

The 100x just adds two zeros to your phone number so when you add your age, it occupies the two rightmost positions. If you are over 99 years old, it won't work. You would have to multiply by 500 rather than 50 so that there would be three positions for your age.

 

[mmatlas]

THANK YOU LOREN! You are the best! I knew the 50 played a role, just didn't know how!