Puzzle 164 | Science and Mathematics

Problem proposed by Bruno Holland and Samuel Vitosa

There are 68 coins in a bag, each with different weights. Describe how to find the heaviest and lightest coin using a weight of 100 on a binary scale. Note: On the two-scale scale, you can put objects on the pans and see which group of objects is heavier.

Send your solution to [email protected]. Don’t forget to include your name, city and school, if possible. We will publish the solution next Sunday.

163- Solve the puzzle.

Jonas and Amanda’s count went in the same direction and counted the same number of students in the circle. From Marcus to Nair, as Amanda counts, there are 201-14 = 187 students. This result must be the same as in the number of Jonah. Since Nair was number 3 in Jonah’s count, that means Jonah counted down to the last student in the circle and started counting 3. If he started at 37, then we must subtract 36 from the total number of students in the circle and then add 3, the result is 187, That is, the total number of students in the circle is 187 + 36−3 = 220. Let’s not forget that Jonas and Amanda are also students in the school, but they were not in a circle. So the total number of students in the school is 220 + 2 = 222.

Bruno Holland Professor in Federal University of Goiás and Samuel Vitosa Professor at the Federal University of Bahia.