Solution Step 0/0
In a museum there was an old clock with Roman numerals. Instead of the familiar IV there was an old-fashioned IIII. Cracks had formed on the face and divided it into 4 parts. The picture shows unequal sums of the numbers in each part, ranging from 17 to 21.
It is said only one crack can be changed, leaving the others untouched, so that the sum of the numbers in each of 4 parts is 20? Which crack is it?
Hint: The crack, as changed, does not have to run through the center of the clock.
It is said only one crack can be changed, leaving the others untouched, so that the sum of the numbers in each of 4 parts is 20? Which crack is it?
Hint: The crack, as changed, does not have to run through the center of the clock.
Explanations
There are three adjacent Xs in IX, X, and XI, and two of them must be in one part. The crack must split IX, not XI, so that the numbers add to 80.[After Boris A. Kordemsky. The Moscow Puzzles: 359 mathematical recreations. 1972]
Check Crack between XI & XII
Check Crack in the midst of IIII
Check Crack between VII & VIII
Check Crack between IX & X
