M=12(p+q)r\displaystyle M = \frac{1}{2}(p + q)rM=21(p+q)r
Work out the value of M M\,M when p=12p = 12p=12, q=8q = 8q=8 and r=11r = 11r=11
108 exam-style questions on Edexcel GCSE Maths Substitution. Each one has a worked solution and a mark scheme showing where the marks go.