Thinking Skills (Logical Reasoning)

Find the odd one out from the following words:

• Fox

• Wolf

• Cheetah

• Snake

Answer explanation

A snake does not have legs, whereas the other 3 animals all have 4 legs (they are quadripeds!)

Hiro likes to mismatch his sock colours. He has blue, red-and-white-striped, black, white, and orange-polka-dot socks. He follows three rules only:

A blue sock must match a red-and-white striped sock.

A red-and-white sock must match with either a blue or black sock.

An orange polka-dot sock must match with a white or black sock.

If Hiro follows these rules, which of these can happen?

• Hiro wears a white sock with a blue sock.

• Hiro wears a white sock with an orange polka-dot sock.

• Hiro wears a black sock with a white sock.

• Hiro wears a black sock with a blue sock.

Answer explanation

If we make a table using the statements given, we can determine this. Alternatively, using the process of elimination, we can figure out which one of the options is possible!

Four students, P, Q, R, S, have different heights. P is taller than Q. R is shorter than S. P is taller than R. P is shorter than S. R is shorter than Q. 

Select the incorrect statement

• S is not the shortest among the four

• Q is taller than S

• P is shorter than S

• R is the shortest among the four

Answer explanation

Arranging statements,

P > Q

S > R

P > R

S > P

Q > R

Combining all S > P > Q > R

Hence Q cannot be taller than S

Summer is trying to build the tallest card house she can in 1 minute. It takes Summer 20 seconds to build the first level of the card house. To build the first level of the card house, she uses 8 cards.

Summer predicts: “If I proceed at the same rate of 10 cards/20 seconds that I have shown with the first level of card house building, I will build a three-level card house in 1 minute.”

Which of the following statements shows the flaw in Summer’s reasoning?

• Summer will be able to make the second and third levels more quickly than 20 seconds because she will have had more practice with card-house making.

• Summer will make more mistakes as she progresses with the card house, causing her to take more than 1 minute to make the house.

• It is impossible to build a card house in 1 minute.

• A card house will have fewer cards on the second and third levels compared to the first level.

Answer explanation

Summer is incorrect because even if she proceeds at the same rate (cards set up/time), there are fewer cards required on the second and third levels so the card house should take less than 1 minute to complete. The incorrect options assume either that it is impossible to build a card house in 1 minute OR that the rate of cards set up/time is different from what Summer stipulates. 

In ancient Egypt, pyramid workers would say “gengro yatju” when wishing other pyramid workers “good building”. Upon the pyramid workers’ return, the children would ask “Ern yatju gengro?”, which meant “Was building good”? The pyramid workers would either reply “Ern gengro yatju” (“was good building”) or “Ern gangro yatju!”

If gangro symbolises the opposite of gengro, what does “Ern gangro yatju” mean?

• was bad building

• was hard building

• building was not easy

• was cold building

• building happy was

Answer explanation

gengro yatju = good building

Ern yatju gengro = was building good

Ern gengro = was good building

We can deduce from the information that:

gengro = good

yatju = building

ern = was

gangro = opposite of good = bad

Therefore:

Ern gangro yatju = was bad building