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KCC's Quizzes AQQ231 about Birthdays and Cake Candles



		

			

									
					    KCC
					
							

			
				
									
											
			
			
				
  •  Analog Employees  

			
			
			    	
			                    
                
				                on Mar 29, 2023 
				
			
			
		


				
		

		    		    
		    
		    	
			
 


Mary celebrates her birthday every year from the very first year. 


The number of candles on her cake used reflects her age : 1 at age of 1, 2 at age of 2, 3 at age of 3 etc…


 Up to now, she has blow out a total of 946 candles.


Questions:


    

  1. How old is Mary today?
    2. 

  2. In an other family, there are 2 sisters, Ann and Helen. Helen is 5 years younger than Ann. They both follows the same scenario for the candles as Mary. The cumulated candled used by the 2 sisters is 1687. How old are Ann and Helen?
    3. 



P.S. If you think there are still colleagues or friends (internal or external) you think who can be interested in those quizzes, please let let them know....


Kuo-Chang

										


				Hide replies until user replies.

[edited by: emassa at 1:54 PM (GMT -4) on 29 Mar 2023]
				

					


				
				
		

			
						
									
									
						
						
			
			
			
			
		


        
        

					

			






	
















	

	

					



			


				
	









	
    
	

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    •  Analog Employees  
    
            
			                            
                        
                on Mar 29, 2023 11:23 PM
            
            
												
						in reply to Sona22
					
									
    
	
    

		
		
    
					
    Thank you Sona for your feedback! Rendez-vous next week!
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
			                            
                        
                on Mar 29, 2023 11:25 PM
            
            
												
						in reply to RolaSand
					
									
    
	
    

		
		
    
					
    Guten Tag Roland! Yes, as already said to Fons: any method is valid as long as the answer is correct!
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
				
						
				
				
		
		
    
			
		
    
	
    

    

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                on Mar 30, 2023 9:30 PM
            
            
					
      
	
      

		
		
      
					
      Answers:
      1. Mary is 43yrs
      

      2. Helen is 38yr,s Ann 43yrs
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
			                            
                        
                on Apr 5, 2023 12:16 AM
            
            
												
						in reply to TReinhardt
					
									
      
	
      

		
		
      
					
      Thanks Timo for your reply! In few days the official answers will be published!
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
			                            
                        
                on Apr 7, 2023 5:41 PM
            
            
					
      
	
      

		
		
      
					
      OK, let's publish now the official answers...
      

        

      1. The total number of candles used by Mary is thus : S=1+2+3+4…+n where n is the today age. S = n(n+1)/2 = 946, or n² + n = 1892 or n² + n -1892=0
        2. 

      

      n = [-1 +/-SQRT(1+4*1892)]/2 = 43 years old
      

        

      1. Ann has consumed n(n+1)/2 candles in total and Helen m(m+1)/2. Since Helen is 5 years younger, we have m=n-5, both sisters have used:
        2. 

      

      n(n+1)/2 + m(m+1)/2 = n(n+1)/2 + (n-5) (n-4)/2 = n² - 4n +10 = 1687
      

      Hence : n² - 4n - 1677 = 0 or n = [4 +/-SQRT(16+4*1677)]/2
      

      n = 43 this the Ann’s age
      

      m=n-5 = 38 is the Helen’s age
      

      There are also solutions using Excel spreadsheet that was opted by many
      

      Big applause for our 4 first winners:
      

      1. Jeff EVANKO, ADI, Key Account Manager, Cleveland (OH, USA
      

      2. John WISNIEWSKI, ADI, Snr Field Application Engineer, Flourtown (PA), USA
      

      3. Rahul NOOLU, ADI, Design Verification Manager, Bengaluru, India
      

      4. Gaetano PIARINO, ADI, Key Account Manager, Milan, Italy
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
				
						
				
				
		
		
      
			
		
      
	
      

      

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