Civil Service Practice
Start free

Professional · Civil Service Exam

Logic, assumptions and conclusions

These items ask what follows necessarily from what you are given - or what a statement takes for granted without saying.

For a syllogism, take the statements as true even when they are absurd. The question is whether the conclusion follows, not whether it is factually right, and importing what you know about the world is the fastest way to get one wrong.

For an assumption item, test each option by denying it. If the statement still stands with the option false, it was not assumed. The trap on offer is almost always an option that simply repeats something the statement already said: true, and therefore not an assumption.

Conditional statements reverse badly. `If it rains, the game is cancelled` tells you nothing about what happens when it does not rain.

Worked examples

Try these, then read why.

Written for this platform and generated from the same bank the practice sets draw on. Every wrong option is explained, because knowing why a distractor was tempting is most of the learning.

Assume both statements are true. Which conclusion follows?

Some budget officers are chemists.
All chemists are bonded officers.
  1. ASome budget officers are bonded officers. (correct)
  2. BSome budget officers are not bonded officers.
  3. CAll bonded officers are budget officers.
  4. DAll budget officers are bonded officers.

At least one of the budget officers is a chemist, and everyone who is a chemist is a bonded officer, so at least some budget officers are bonded officers. Follow the shared term through both statements, and claim no more than they allow. A conclusion that reverses the terms, or upgrades some to all, does not follow.

  • B Nothing in the premises establishes an exception.
  • C This swaps the two terms. The premises support a claim about the first group, not about the second.
  • D The premises do not license a claim about every member of the group.

Statement: The school added a daily reading hour so that pupils would score higher on the year-end comprehension test.

Which one of the following is assumed in the statement above?
  1. AParents asked the school to set aside time for reading.
  2. BTime spent reading affects how well pupils comprehend what they read. (correct)
  3. CThe pupils' scores will rise this year.
  4. DThe school has added a daily reading hour.

Test each option by denying it: if the statement still stands, the option was not assumed. Deny the key here and the statement falls apart - without that link the added hour could not raise the scores it was added to raise. The commonest trap is an option that simply repeats the statement. Anything already said is not an assumption, however true it is.

  • A Who proposed the reading hour has no bearing on why it was added.
  • C This is the hoped-for result of the plan, which is the opposite end of it from an assumption.
  • D The statement says this directly, so it is not something taken for granted.

Assume both statements are true. What follows?

If the transcript bears no dry seal, then it is sent back to the school.
It is not sent back to the school.
  1. AThe transcript bears no dry seal.
  2. BIt is sent back to the school.
  3. CIt is not sent back to the school.
  4. DThe transcript bears a dry seal. (correct)

The rule says that whenever the transcript bears no dry seal, it is sent back to the school. The second statement tells you the result did not happen, so the condition cannot have held either. A conditional runs one way only. Knowing the result happened tells you nothing, and ruling out the condition tells you nothing.

  • A Working backwards from the result is not valid: the result can have other causes.
  • B This restates the rule's result without the fact that would license it.
  • C Ruling out the condition does not rule out the result.

Practise this properly.

Three examples show you the format. Finding out whether logic, assumptions and conclusions is actually costing you marks takes a measured set, which is what the free diagnostic is for.

Take the free diagnosticHow it works

Other topics