Solving simultaneous equations

Maths

The cost of 1 protractor is 30 pence. If I spent £2.70, how many did I buy?

A compass costs 50 pence. 8 protractors and 3 compasses costs £8.70. What is the cost of a protractor?

1 compass and 1 protractor costs £1.10. 2 compasses and 1 protractor costs £1.60. What is the cost of a compass?

If 10 compasses and 3 protractors cost £4.20. 10 compasses and 6 protractors cost £5.40. Find the cost of 1 protractor.

If 10 compasses and 3 protractors cost £4.20. 10 compasses and 6 protractors cost £5.40. Find the cost of 1 compass.

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?