S=12(u+v)t\displaystyle S = \frac{1}{2}(u + v)tS=21(u+v)t
Work out the value of S S\,S when u=10u = 10u=10, v=20v = 20v=20 and t=7t = 7t=7
108 exam-style questions on Edexcel GCSE Maths Substitution. Each one has a worked solution and a mark scheme showing where the marks go.