Solution Step 0/0
Victor asked, “What plane did you fly during the air parade?“
His father, the pilot, sketched the formation of 9 planes.
“The number of planes to the right of me multiplied by the number of planes to the left of me is 3 less that it would have been if my plane had been 3 places to the right of me.“
What plane on the sketch counting from left Victor's father flew in during the air parade?
His father, the pilot, sketched the formation of 9 planes.
“The number of planes to the right of me multiplied by the number of planes to the left of me is 3 less that it would have been if my plane had been 3 places to the right of me.“
What plane on the sketch counting from left Victor's father flew in during the air parade?
Explanations
Victor's father flew in the third plane. In that case 2 planes are to the left of him and 6 to the right. Multiplied right by left it makes 6 x 2 = 12.In case his plane is moved three places to the right, his position would be 6th, resulting in the 5 planes to the left and 3 to the right. Multiplied right by left it makes 3 x 5 = 15.
The fastest way to solve the challenge would be to create a table shown in the diagram.
[After Boris A. Kordemsky. The Moscow Puzzles: 359 mathematical recreations. 1972]
Check 2nd plane
Check 3rd plane
Check 5th plane
Check 7th plane
