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?..................
Square a number ending with 5
Ex 1:
5 X 5 = 25
Let us take another example 15 X 15
Step :1
Take the first digit which is unit digit of the number 5 at both right side (15) and left side(15).
Step :2
Multiply those digits 5 X 5 = 25 and keep it aside.
Step : 3
Now you pick up the Tenth digit which is 1 at both right (15) and left side (15)
Which is 1 & 1
Step : 4
Add 1 to left or right side which is (1+1) X 1
Step : 5
2 X 1 = 2
Step : 6
Now you club Tenth digit result and Unit digit result which is 2 &25 = 225
Ex 2:
75 X 75
Unit Digit à 5 X 5 = 25
Tenth Digit à (7+1) X 7 = 56
