Question 15
Children in Kangcity enjoy card games. An exchange machine offers two operations: I, exchange one white card for four red cards; II, exchange one red card for four white cards. Alila starts with four white cards. After exactly 11 exchanges, he is said to have 31 cards in total. How many of those cards are red?
Original source choices (retained):
A. 21
B. 17
C. 14
D. 27
E. 11
Source consistency task: test the stated total after 11 exchanges. Then separately examine what happens if 31 is corrected to 37, including whether the red count is uniquely determined. Original wording and choices are retained.
Original source choices (retained):
A. 21
B. 17
C. 14
D. 27
E. 11
Source consistency task: test the stated total after 11 exchanges. Then separately examine what happens if 31 is corrected to 37, including whether the red count is uniquely determined. Original wording and choices are retained.