I suppose your problem was with "alloc" but anyway, for the sake of other users that may encounter similar problems, you should always explain how you fixed your code

never mind i fixed it

@interface DataManager : NSObject {

	int correctAnswers;
	int incorrectAnswers;

	int raceTime;
	int speed;
	int score;

}

@property(readwrite) int correctAnswers;
@property(readwrite) int incorrectAnswers;
@property(readwrite) int raceTime;
@property(readwrite) int speed;
@property(readwrite) int score;

+ (DataManager*)sharedData;

@end

#import "DataManager.h"

@implementation DataManager
@synthesize score,speed,correctAnswers,incorrectAnswers,raceTime;

static DataManager *DataManager_Singleton = nil;

+(DataManager *)sharedData
{
	if (nil == DataManager_Singleton) {
		DataManager_Singleton = [[DataManager_Singleton alloc] init];
	}
	return DataManager_Singleton;

}

@end

Whenever I type [[DataManager sharedData] setScore = 100] or any value in another class(cocos2d layer), it remains 0.