What is one-third of a number less than nine is equal to seven as an equation?

The equation is given by:

Let the number be denoted by x.

Now, we are given a word phrase as follows:

One-third of a number less than nine is equal to seven.

Now this word phrase could be mathematically expressed as a equation by:

  one-third of x is: 1/3 x

and this number less than 9 is given by:

Now, this number is equal to 7.

i.e. we finally have:

use this formula:

p(a\b) = p(a and b)/p(b).

take it from here.