Logic.

In my early days I loved the idea of owning a car but at that time I did not have the resources to buy one. It happened that I saw in the street a parked three wheeler which looked rather sporty. On investigation I found I could just afford to buy one. There was a most remarkable feature that stuck in my mind. Although powered by a small capacity motor bike engine it would streak away from the traffic lights leaving conventional cars far behind.

I love playing chess but felt I did not have the IQ to challenge the grandmasters until I realised like the three wheeler it is not the capacity of power that is important but how you use what you have. The grandmaster looks for patterns and selects a small number of possible moves. In fact the grandmaster spends less time than ordinary players in deliberating which is the best move.

How I solve logic problems is to select a part of the problem that is in the question and work backwards. The answer is usually concealed by misdirection, as you can see in the following examples.

I stepped into the lift on the ground floor with three other people. The lift stopped at the second floor. One person got out and four got in. At the third floor four more people got in but before
the next floor the cable broke and all the passengers died. How did I survive? In order to survive I could not be in the lift. So I look for how and when I could get out of the lift. I have deliberatively made the answer obvious as this is a demonstration of thinking and the answer is I got out at the second floor.

Often my first assumption is incorrect and I need to start at the beginning.

A boy and a doctor were in a speed boat. The boy is the doctor's son but the doctor is not the boy's father. Who is the doctor? The information is deliberately presented in a way to conceal the answer. I know the boy is a son and normally you need two parents. So if it is not a father, the answer must be mother.

Sometimes facts tell you where to concentrate your attention.

A man nailed a horse shoe to the trunk of a tree just at the height of his nine year old son. The tree grows three inches each year. After three years where will the horse shoe be?

I need to think through the information and remember facts are there to mislead me. How does a tree grow? The horse shoe should be in the same place as a tree grows from above.

Just to recap on how I think about solving logic problems.

I use quality thinking by selecting the key information and think it through.
I remember information is presented to confuse and hide the answer. I remember words can have several meanings or be used as names.

I went to the market on Friday and returned two days later on Friday. How is that possible?

If you are stuck, look at the last statement in my recap on thinking about solving logic problems. In this situation one can think of the Friday used. Friday can have a double connection as it could be that Friday was a horse I travelled on there and back. Friday does not have to be a weekday.