Question 726946
Just translate into symbolism.  Use a variable for the unknown number.


n is the number.
25% of a number is subtracted from 3/5 of the number,...
{{{(3/5)n-0.25n}}},


the result 42,...
{{{(3/5)n-0.25n=42}}}


So solve the equation.  First, you need to know how to translate from the description into symbols, as I have done.