Today was Catherine´s birthday. She turned 24. Catherine is twice as old as Ryan was when Catherine was as old as Ryan now. How old is Ryan now?..................
Divisibility of any number by 7
To check divisibility of any number by 7, use 5 as a check multiplier.
Multiply the unit digit with check multiplier & then add this answer to the number after removing the units digit.If the answer is evenly divisible by 7 then the number is evenly divisible by 7.
Example:
Let's check the whether 952 is divisible by 7.
Step 1: Unit digit of given number is 2.Multiply 2 by 5. You get 10
Step 2: Remove unit digit from given number, you get 95.Add 10 (got from step 2) to this no.You get 105. 105 is divisible by 7. Therefore 952 is divisible by 7.
Actual answer is: 136
Let's take another example: 104706
Step 1: Take unit digit and multiply by check multiplier 5, you get 30
Step 2: Add 30 to 10470 (got after removing unit digit), you get 10500,which is divisible by 7
Therefore 104706 is divisible by 7
Actual answer is: 14958
Let's take another example of a number which is not divisible by 7
1038.
Step 1 : 8*5 = 40
Step 2 : 103 + 40 = 143, which is not divisible by 7.
