Radio Astronomy Systems Research Group

One night, there were 4 people that came across a bridge they must cross. Because the bridge was very old an full of holes, it was impossible to cross in the dark. Luckily, there was a single flashlight which they must carry with them as the cross the bridge. The bridge also had a weight limit and would collapse if more than two of the people tried to cross at the same time.

Each person walked at a different speed and so when two traveled together, they would both walk the same speed as the slower of the two. Their speeds are as follows:
Person 1 will take 1 minute to cross the bridge.
Person 2 will take 2 minutes.
Person 3 will take 5 minutes.
Person 4 will take 10 minutes.

What is the shortest amount of time it will take to get all 4 people across the bridge? ¹⁾

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Using the 8 digits 4 4 3 3 2 2 1 1, create an 8 digit number in which there is 1 digit between the two 1's, 2 digits between the two 2's, 3 digits between the 3's and 4 digits between the 4's. ²⁾

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If you were to rotate the year 1881 180 degrees, it would still read 1881. What in the next year after 1881 that will also read the same after being rotated 180 degrees? ³⁾

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What are the next two letters in this sequence? ⁴⁾

   W A T N T L I _ _

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A man had three sons. One day, he was visiting with a friend of his. The friend asked how old his sons were, and the man responded by giving him clues about their ages. First, he told the friend that the product of his sons ages was 36. Next, he said the sum of their ages was the same as the friends house number. The man then said that the eldest son played the theremin. Using these three clues, the friend was able to figure out each sons age. Can you? ⁵⁾

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Using the digits 8,8,3 and 3 once each, create an expression that equals 24. You may only use subtraction, addition, multiplication and division. ⁶⁾

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The sundial is the timepiece with the fewest moving parts. What timepiece has the most moving parts? ⁷⁾

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The square piece of paper shown below has a hole cut out of it. With only a single cut, find a way to cut and recombine the paper so the hole is in the center of the paper. ⁸⁾

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How can you speak in English for a full minute without using the letter 'a'? ⁹⁾

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How many different ways can you arrange four colors in this pattern without having adjacent colors? ¹⁰⁾

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