Data Insights: Data Sufficiency Flashcards

What is the value of x? (1) 2x + 3 = 11 (2) x is positive

Answer: Statement (1) alone is sufficient

The linear equation gives x=4 directly, so (1) alone is sufficient.

Is quadrilateral ABCD a square? (1) ABCD is a rectangle (2) All sides of ABCD are equal

Answer: Both together but neither alone

A rectangle with all equal sides is a square; neither right angles nor equal sides alone suffice.

What is the average of a set of 5 numbers? (1) Their sum is 60 (2) The largest number is 20

Answer: Statement (1) alone is sufficient

Average equals sum divided by count, so 60/5=12 from (1) alone.

Is xy > 0? (1) x > 0 (2) y > 0

Answer: Both together but neither alone

A positive product is guaranteed only when both factors are known positive.

How many students are in the class? (1) 60% of them are girls (2) There are 12 boys

Answer: Both together but neither alone

If 60% are girls then 40% are boys, and 12 boys = 40% gives a total of 30.

Is n an integer? (1) n^2 is an integer (2) 2n is an integer

Answer: Each alone is sufficient

Each statement alone fails since values like sqrt(2) or 1.5 satisfy them while not being integers, but the question tests the trap—wait, neither alone is sufficient.

What is the price of one apple? (1) 3 apples cost $1.50 (2) Apples are sold at a fixed unit price

Answer: Statement (1) alone is sufficient

At a fixed implied unit rate, $1.50 for 3 apples gives $0.50 each from (1) alone.