Page 149 - NUMINO Challenge_C2
P. 149
Answer
Key
3 problem, the score is an odd number. After two 2 Order 1st 2nd 3rd 4th
problems, an odd number is added or Color of Sock Red Blue Red Red
subtracted from an odd number; therefore, the (Blue) or
score is an even number. Therefore, when Blue
Kenny solves an odd number of problems, the
score is an odd number and when he solves an In the unluckiest case, you must pick out 2 socks.
even number of problems, the score is an even
number. Therefore, after 15 problems, Kenny's 3 You need to pick out one sock that has the
score is an odd number. same color as the pair of socks you made in the
2nd order, and pick out another sock. Therefore,
4 Two students are involved when they shake to get a pair of matching socks you need to pick
out at least 3 1 1 5 socks.
hands with each other; therefore, the number of
students who shake hands is an even number. If Problem solving
students shake hands an even number of times,
then the total number of handshakes is an even 1 In the unluckiest case, you must pick out three
number. If students shake hands an odd number
of times, then the total number of handshakes is different socks. When you pick out another sock,
equal to (Total number of handshakes) (Total you certainly get a pair of matching socks.
number of handshakes made even number of Therefore, you must remove at least
times), which is (even number) (even number) 3 3 3 1 10 socks.
(even number).
Therefore, the sum of odd numbers should be 2 When you first pick out two of each red, blue,
an even number. Therefore, the number of
students who shake hands an odd number of and purple marbles, and pick out another
times is an even number. marble, you'll certainly get three marbles of the
same color. Therefore, you need to pick out at
least 2 2 2 1 7 marbles.
5 Principle of Drawers p.42~p.43
Example 1, 3 1, 2 4 Type 5-2 Number of People with the Same Birthdays p.46~p.47
3
Example 1 2 1 The unluckiest case is when all seven students
have different birthdays.
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Type 5-1 Removing Socks of the Same Color p.44~p.45
1 Order 1st 2nd 3rd 4th 2 The unluckiest case is when each day is the
birthday of a student. When there is one more
Color of Sock Red student, then there are 2 students that have the
Red Blue or same birthday. Therefore, at least
7 1 8 students are needed.
Blue
In the unluckiest case, you must pick out 3 socks.
NUMINO Challenge C2
Key
3 problem, the score is an odd number. After two 2 Order 1st 2nd 3rd 4th
problems, an odd number is added or Color of Sock Red Blue Red Red
subtracted from an odd number; therefore, the (Blue) or
score is an even number. Therefore, when Blue
Kenny solves an odd number of problems, the
score is an odd number and when he solves an In the unluckiest case, you must pick out 2 socks.
even number of problems, the score is an even
number. Therefore, after 15 problems, Kenny's 3 You need to pick out one sock that has the
score is an odd number. same color as the pair of socks you made in the
2nd order, and pick out another sock. Therefore,
4 Two students are involved when they shake to get a pair of matching socks you need to pick
out at least 3 1 1 5 socks.
hands with each other; therefore, the number of
students who shake hands is an even number. If Problem solving
students shake hands an even number of times,
then the total number of handshakes is an even 1 In the unluckiest case, you must pick out three
number. If students shake hands an odd number
of times, then the total number of handshakes is different socks. When you pick out another sock,
equal to (Total number of handshakes) (Total you certainly get a pair of matching socks.
number of handshakes made even number of Therefore, you must remove at least
times), which is (even number) (even number) 3 3 3 1 10 socks.
(even number).
Therefore, the sum of odd numbers should be 2 When you first pick out two of each red, blue,
an even number. Therefore, the number of
students who shake hands an odd number of and purple marbles, and pick out another
times is an even number. marble, you'll certainly get three marbles of the
same color. Therefore, you need to pick out at
least 2 2 2 1 7 marbles.
5 Principle of Drawers p.42~p.43
Example 1, 3 1, 2 4 Type 5-2 Number of People with the Same Birthdays p.46~p.47
3
Example 1 2 1 The unluckiest case is when all seven students
have different birthdays.
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
Type 5-1 Removing Socks of the Same Color p.44~p.45
1 Order 1st 2nd 3rd 4th 2 The unluckiest case is when each day is the
birthday of a student. When there is one more
Color of Sock Red student, then there are 2 students that have the
Red Blue or same birthday. Therefore, at least
7 1 8 students are needed.
Blue
In the unluckiest case, you must pick out 3 socks.
NUMINO Challenge C2
