Pearson Edexcel International GCSE (9–1) · MATHEMATICS A · Chapter
Algebra 6
17 practice questions
Practice questions
1–4 of 4 · Hard
Question 1
4 marks · Hard
Answer and see the solution →The time, T seconds, for a chemical reaction is directly proportional to the square of the temperature, t °C. The reaction takes 32 seconds at 40°C.
a) Write down the formula for T in terms of t.
b) Calculate the time for the reaction at 70°C.
c) Find the temperature if the reaction takes 50 seconds.
(a)[1 mark]Write your answer in the form T = k t^2.
(b)[2 marks]Give your answer to 1 decimal place if necessary.
(c)[1 mark]Find t, the temperature, when T = 50.
Question 2
4 marks · Hard
Answer and see the solution →The cost, C dollars, of producing a metal sphere varies as the cube of its radius, r cm. A sphere of radius 5 cm costs $120.
a) Find the formula for C in terms of r.
b) What is the cost of a sphere with a radius of 7 cm?
c) A company wants to make a sphere for $405. Work out the radius of this sphere.
(a)[1 mark](b)[2 marks](c)[1 mark]Question 3
4 marks · Hard
Answer and see the solution →The cost of producing a metal container varies as the square of its base diameter and is inversely proportional to its height . When cm and cm the cost is £64.
(a)[1 mark]Write down a formula for in terms of and .
(b)[3 marks]Calculate the cost when cm and cm, giving your answer to 2 decimal places.
Question 4
3 marks · Hard
Answer and see the solution →Simplify the following using the rules of indices. Write your answer with positive indices only: