UCAT Decision Making 6

Question 1

A logic puzzle: If A is true, B is false. If B is false, C is true. A is true. What is C?

Accepted Answer

True

Answer

A is true → B is false → C is true. The chain of conditionals resolves fully.

Question 2

A map shows 3 routes from X to Y. Route 1: 60 km at 60 km/h. Route 2: 80 km at 80 km/h. Route 3: 90 km at 60 km/h. Which is fastest?

Accepted Answer

Routes 1 and 2 are equally fast

Answer

Time = distance/speed. Route 1: 60/60 = 1h. Route 2: 80/80 = 1h. Route 3: 90/60 = 1.5h. Routes 1 and 2 both take 1 hour.

Question 3

A company's profit increased by 25% in Year 1 and decreased by 20% in Year 2 from the Year 1 figure. Compared to the start, profit is:

Accepted Answer

The same as the original

Answer

If start = 100: after +25% → 125. After −20% of 125 → 125 × 0.8 = 100. Back to original.

Question 4

Four statements about a number N: (1) N is even. (2) N is divisible by 5. (3) N > 20. (4) N < 30. Which number satisfies all four?

Accepted Answer

30 is excluded; the answer is that no number in range works — wait: N=25 is odd. N=20: 20 is even, divisible by 5, but not > 20. So no number satisfies all four.

Answer

Even numbers divisible by 5 between 20 and 30 (exclusive): candidates are 10, 20, 30. 20 is not >20; 30 is not <30. There is no such number — this tests recognising when no solution exists.

Question 5

In a population, disease prevalence is 1%. A test has 95% sensitivity and 90% specificity. What is the approximate positive predictive value?

Accepted Answer

About 9%

Answer

Using 10,000 people: 100 diseased, 9,900 not. True positives = 95. False positives = 990. PPV = 95/(95+990) ≈ 8.8% ≈ 9%. Low prevalence causes low PPV even with a good test.

UCAT Practice Test

UCAT Practice Test

UCAT Decision Making 6