Pearson Edexcel International GCSE (9–1) · MATHEMATICS A · Unit
Unit 6
104 practice questions
Topics covered
Practice questions
21–30 of 104
Question 21
4 marks · Easy
Answer and see the solution →The cost, C dollars, of printing a set of posters is directly proportional to the number of posters, n.
When 50 posters are printed, the cost is $80.
(a)[1 mark]Write the formula for C in terms of n.
(b)[2 marks]Calculate the cost of printing 120 posters.
(c)[1 mark]How many posters can be printed for $200?
Question 22
1 mark · Easy
Answer and see the solution →Simplify the following expression:
Question 23
1 mark · Easy
Answer and check →Evaluate 2^{3} \times 2^{-1}.
Question 24
2 marks · Easy
Answer and see the solution →If a = 3 and b = -2, calculate the value of the expression:
Question 25
2 marks · Normal
Answer and see the solution →Given that is directly proportional to and when , find the value of when .
Question 26
2 marks · Normal
Answer and see the solution →The length, metres, of a metal rod is directly proportional to its temperature increase, degrees Celsius. If the rod is 102 cm long when it is heated by 20 ∘C (assume it starts at 0 cm at 0 ∘C), what is its length after a temperature increase of 37.5 ∘C? Give your answer in centimetres.
Question 27
2 marks · Normal
Answer and see the solution →Simplify the following expression and write your answer with positive indices only:
Question 28
2 marks · Normal
Answer and see the solution →The kinetic energy of a moving object varies as the square of its speed .
Explain in words what happens to the kinetic energy if the speed of an object is trebled.
Question 29
3 marks · Normal
Answer and see the solution →A factory produces widgets. The number of widgets, , produced is directly proportional to the number of workers, , employed.
(a)[1 mark]On a certain day, 50 workers produce 600 widgets. Write the formula connecting and .
(b)[1 mark]How many widgets would 90 workers produce?
(c)[1 mark]How many workers are needed to produce 960 widgets?
Question 30
2 marks · Normal
Answer and see the solution →Simplify the following expression, writing your answer as a power of only: