B.1145. You can cut a 6cm x 8cm piece of paper into seven squares without any left-over, so that the side of each square is a whole number of cm, only two ways. What is the total length of the cuts in each case?

B.1146. The sum of the ages of Henry and his father is 33 years. 15 years from now Henry is going to be half as old as his mother, and 18 years from now he is going to be half as old as his father. How old are Henry and and his parents now?

B.1147. If you continued the diagrams on the following picture, how many little squares would the 30th diagram contain?

B.1148. Rita Half drew the following polygon into her notebook. She states that she can draw a straight segment from any grid point on the perimeter of the polygon, so that the segment would half the area of the polygon, and that the other end of the segment is a grid point on the perimeter, too. Is Rita correct, or not?

B.1149. Find the smallest positive whole number in which the product of the digits is 648, and any two neighboring digits are different.

B.1150. James Bond is preparing to defuse a time-bomb. There are four kinds of wires in the mechanism: red, yellow, blue and green. He has to cut all the wires in order to defuse the bomb, but he can cut only one wire at a time. He learned that only one event causes the bomb to blow up, but he cannot remember which one: if you cut the red wire before the yellow, or if you cut the blue wire before the red. Find all possible ways to defuse to bomb without blowing it up.

B.1151. There are two strange people living in Nevermind country: Peter, who lies on every Monday, Tuesday and Wednesday, but says the truth on all the other days; and Paul, who lies on every Thursday, Friday and Saturday, but tells the truth on all the other days. One day they said:

Peter: “Yesterday I had a lying day.”

Paul: “Yesterday I had a lying day, too.”

What day of the week was this on?

B.1152. Tom is twice as old as Jerry, but 4 years ago Tom was three times as old as Jerry. How old are they now?

Please send your solutions here.

The Sharma Kamala Educational Trust is sponsoring the participation of students from India. So, if you are a student living in India, please, send your solutions to: Group B from India

Back to Paul Erdős International Math Challenge
Current Standings in 2017-2018