Jack enjoys completing brain teaser questions. During his coffee break he is working on the following question:
A decimal number is written on a card.
You have three clues to help you work out the number on the card.
Clue 1: The number is between 5 and 12 inclusive.
Clue 2: The number is a multiple of 2·3.
Clue 3: The square of the number is greater than 50 but less than 120.
What is the decimal number on the card?
Help jack work out the answer to this brain teaser question.
Answer:
Since the number is a multiple of 2.3 and is between 5 and 12 the options are
6.9, 9.2, 11.5
However, 6.9 squared is less than 50 and 11.5 squared is greater than 120
Therefore, the decimal on the card can only be 9.2.