GCSE · Formulae & rearranging

Substituting into formulaeExam-style questions

Why substitution is "replace the letter, keep the structure", why negatives must go in with brackets, and why the order of operations still rules once the numbers are in.

15 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 1Level 2Level 3Level 4Level 5
  1. 1
    T=2πlgT = 2\pi\sqrt{\dfrac{l}{g}}

    Work out the value of TT when l=2.5l = 2.5 and g=9.8g = 9.8 Give your answer correct to 3 significant figures. (2 marks)
    Level 2 · 2 marksTry it
  2. 2
    The cost, £CC, of hiring a hall for dd days is given by

    C=5d+20C = 5d + 20

    Work out the cost of hiring the hall for 77 days.
    Level 2 · 2 marksTry it