Subject :IMO Class : Class 8
100 cards are placed face down in a line. Alice turns every second one over, starting with the second in line. Brenda then turns over every third card that is still face down (so starts with the fifth card in the line). After this, how many cards remain face down?
A 24
B 28
C 34
D 46
Ans 1:
Class : Class 1
Ans 2:
Class : Class 8
explain me plz...