1)I AM greater than 15 and less than 40 if you double me I become a number that ends in 0 1/5 of me is equal to 5

2) if you multiply me by 2 ,I become a number greater than 20 and less than 40 if you multiply me by 6,I end in 8 if you multiply me by 4 I end in 2
Help me figure out who I am

2 answers

1) 25
1/5x = 5
x = 5*5
x = 25
2)18
It states that when it is multiplied by 2 it is between 20 and 40 so divide both 20 and 40 by 2 and that shows that your range of numbers is between 10 and 20.
18*2 = 36 between 20 and 40
18*6 = 108
18 * 4 = 72
1)

(1/5)x = 5
x = ?

2)
From the first clue the number must be between 11 and 19
Take it from there.