Exploring systems of equations

Maths

If p=11 and p+q=20. What is the value of q?

If p+1=6 and p+q+1=7, what is the value of q?

If p+q=11 and 2p+q=1, what is the value of 3p+2q?

If a protractor costs 50p and a ruler costs 60p, what is the cost of 3 protractors and 2 rulers?

I want to buy 3 rulers and 3 protractors. If they cost 40 pence each, how much will I spend?

Given that y=13, which of the following expressions is equal to 195?

If x=4 and y=5, which of the following expressions is equal to 24?