1).
Call the number 'N'.
The difference between the number and ten isĀ (N-10).
Twice the difference between the number and ten isĀ 2(N-10).
That's all the question asks for.Ā There's no way to find what number 'N' is.
2).
Call the mystery number 'Q'.
Twice the number isĀ 2Q.
IfĀ 5Ā is subtracted from twice the number, you haveĀ (2Q - 5).
But it tells us that the result would beĀ 11 .
So writeĀ (2Q - 5) = 7Ā Ā and solve that simple equation to find what 'Q' is.Ā
3).
Call the mystery number 'Z'.
The quotient of the number and 4 isĀ Z/4.
If you add 5 to the quotient of the number and 4, you haveĀ (Z/4 + 5).
It tells us that the result would beĀ 10.
So writeĀ (Z/4 + 5) = 10 and solve that simple equation to find what 'Z' is.
4).
I'm sorry.Ā I don't know what this question is asking for.