Page 152 - NUMINO Challenge_C2
P. 152
4 Road B leads to the treasure. 2 If there are 1, 2, or 3 false statements among
Problem solving the 5 statements, then another statement will be
false; therefore, there is a contradiction.
1 Assume that each box contains the gold coins If all five statements are false, then is also
false; therefore, there is a contradiction.
and find the case where only one of the Therefore, since the statement says that
statements on the boxes is true. besides all the other statements are not true,
then is true and the other statements are
ABC false.
Gold Coins are in Box A True 3 If A is true
Gold Coins are in Box B Contradictory A: Truth : The lion is either in room B or C.
B: Lie : The lion is not in room A nor D.
Gold Coins are in Box C Contradictory C: Lie : The lion is not in room C.
D: Lie : The lion is not in room D. Therefore, the
If the gold coins are in box B and box C, then lion is either in room B or C, and also in room D.
two statements are true, Therefore, there is a Therefore, there is a contradiction.
contradiction. If the gold coins are in box A, If B is true
then there is only one statement that is true; A: Lie : The lion is not in room B nor C.
therefore, it's logically true. Therefore, box A B: Truth : The lion is either in room A or D.
contains the gold coins. C: Lie : The lion is not in here.
D: Lie: The lion is in here.
2 Assume that each student received 100 points Therefore, the lion in room D which is logically
correct.
and find the case where only 1 student is
telling the truth. 4 If you assume that the person who is talking is a
Student who David's Susan's Jeff's Grace's liar, then "At least one of us is a liar." is a lie;
therefore, the two people are both truth-tellers.
Received 100 Points Statement Statement Statement Statement But, since you assume that the person who is
talking is a liar, it is logically incorrect.
David Contradictory
Susan Contradictory The person who is talking is a truth-teller.
Jeff
Grace True
Contradictory
Jeff was telling the truth and he is the
student who scored 100 points.
Creative Thinking p.56~p.57
1 Assume that today is Monday. Since Sam lies on
Mondays, then his statement "Yesterday was
Sunday" is a lie. Therefore, today is not Monday.
Assume that today is Friday. Since Sam lies on
Fridays, then his statement "Yesterday was
Sunday" is true. Also, Mary tells the truth on
Fridays, therefore her statement "Tomorrow is
Saturday" is true.
Today is Friday.
Answer Key
Problem solving the 5 statements, then another statement will be
false; therefore, there is a contradiction.
1 Assume that each box contains the gold coins If all five statements are false, then is also
false; therefore, there is a contradiction.
and find the case where only one of the Therefore, since the statement says that
statements on the boxes is true. besides all the other statements are not true,
then is true and the other statements are
ABC false.
Gold Coins are in Box A True 3 If A is true
Gold Coins are in Box B Contradictory A: Truth : The lion is either in room B or C.
B: Lie : The lion is not in room A nor D.
Gold Coins are in Box C Contradictory C: Lie : The lion is not in room C.
D: Lie : The lion is not in room D. Therefore, the
If the gold coins are in box B and box C, then lion is either in room B or C, and also in room D.
two statements are true, Therefore, there is a Therefore, there is a contradiction.
contradiction. If the gold coins are in box A, If B is true
then there is only one statement that is true; A: Lie : The lion is not in room B nor C.
therefore, it's logically true. Therefore, box A B: Truth : The lion is either in room A or D.
contains the gold coins. C: Lie : The lion is not in here.
D: Lie: The lion is in here.
2 Assume that each student received 100 points Therefore, the lion in room D which is logically
correct.
and find the case where only 1 student is
telling the truth. 4 If you assume that the person who is talking is a
Student who David's Susan's Jeff's Grace's liar, then "At least one of us is a liar." is a lie;
therefore, the two people are both truth-tellers.
Received 100 Points Statement Statement Statement Statement But, since you assume that the person who is
talking is a liar, it is logically incorrect.
David Contradictory
Susan Contradictory The person who is talking is a truth-teller.
Jeff
Grace True
Contradictory
Jeff was telling the truth and he is the
student who scored 100 points.
Creative Thinking p.56~p.57
1 Assume that today is Monday. Since Sam lies on
Mondays, then his statement "Yesterday was
Sunday" is a lie. Therefore, today is not Monday.
Assume that today is Friday. Since Sam lies on
Fridays, then his statement "Yesterday was
Sunday" is true. Also, Mary tells the truth on
Fridays, therefore her statement "Tomorrow is
Saturday" is true.
Today is Friday.
Answer Key
