Question 1114775
The statement "20pens and 8 rulers is 32 dollars" forms the equation 20p+8r = 32 where
p = cost of one pen
r = cost of one ruler


We don't have enough information to figure out how much 25 pens and 10 rulers will cost. We would need another statement similar to the first statement given. 


So this problem cannot be answered in its current form. The general rule is that if you have two variables, then you need two equations. Similarly, if you have three variables, you'll need three equations, and so on.