A student wants to use proof by contradiction to prove the following statement.
"The sum of a rational number and an irrational number is always irrational."
Identify the correct starting assumption.
Tick one box.
For all rational numbers aaa and all irrational numbers bbb, a+ba+ba+b is irrational.
There exist a rational number aaa and an irrational number bbb such that a+ba+ba+b is rational.
There exist a rational number aaa and an irrational number bbb such that a+ba+ba+b is irrational.
For all rational numbers aaa and all irrational numbers bbb, a+ba+ba+b is rational.
216 exam-style questions on WJEC A Level Maths 3.2 Algebra and Functions (A-level only), covering 3.2.1 Algebra and Functions (A-level only), 3.2.2 Algebra and Functions (A-level only), 3.2.3 Algebra and Functions (A-level only), 3.2.4 Algebra and Functions (A-level only), 3.2.5 Algebra and Functions (A-level only), 3.2.6 Algebra and Functions (A-level only), and 3.2 Algebra and Functions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.