NRICH: Brian's Number
Brian chooses an integer and operates on it. Work out the largest integer that he could have chosen.
Brian chooses an integer, multiplies it by 4 then subtracts 30. He then multiplies his answer by 2 and finally subtracts 10. His answer is a two-digit number.
What is the largest integer he could have chosen?
This problem is taken from the UKMT Mathematical Challenges.
Age 14 to 16
NRICH provides thousands of free online mathematics resources for ages 3 to 18, covering all stages of early years, primary and secondary school education – completely free and available to all.
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Resource k12
Brian chooses an integer and operates on it. Work out the largest integer that he could have chosen.
Brian chooses an integer, multiplies it by 4 then subtracts 30. He then multiplies his answer by 2 and finally subtracts 10. His answer is a two-digit number.
What is the largest integer he could have chosen?
This problem is taken from the UKMT Mathematical Challenges.
Age 14 to 16
NRICH provides thousands of free online mathematics resources for ages 3 to 18, covering all stages of early years, primary and secondary school education – completely free and available to all.
Do you enjoy thought-provoking questions? If so, this is the place for you.
