Stephen Hawking is the Author of the bestseller “The Brief History of Time” and his daughter explains the universe to readers of all ages in their book “ George's Secret key to the Universe”.
When Lucy was young his father would take his daughter to the terrace and explain about constellations to his daughter and then leaves her alone in the terrace to find few of them all by herself. Lucy finds around 25 groups of stars that appear to her as constellations. She draws 7 patterns of the constellations in her notebook and notes down the number of stars in each of them. She counts 5 stars in first constellation and 15 on next. She counts a number the thrid time and forgets to note it down. The next four constellations she counts 51.53,159,161. Next day her father looks at the notebook and wants to know the number of stars in the third constellation. Lucy only remembers that number of starts counted in each of the constellation followed a pattern 5,15,x,51,53,159,161
a)19 b) 45 c) 16 d) 17

• d)17
  5*3+2=17, 17*3+2=53, 53*3+2=161.......
• 13 years agoHelpfull: Yes(9) No(0)
• d)17
  There are two patterns:
  5,X,53,161 and 15,51,159
  notice 51-15=36 and 159-51=108=36*3
  also, 161-53=108=36*3
  So we can say that in each step thrice of the no. added in the previous step is being added.
  So X=53-36=17
  Now check ...
  5, 17 (i.e. 5+12), 53 (i.e. 17+12*3), 161 (i.e. 53+36*3).
  It all fits.
• 13 years agoHelpfull: Yes(4) No(0)
• d) 17
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• 17
• 13 years agoHelpfull: Yes(2) No(0)
• d)17
• 13 years agoHelpfull: Yes(1) No(0)
• d)
  it follows a pettern.....5*3+2=17....17*3+2=51....
• 13 years agoHelpfull: Yes(1) No(1)
• 17
  Its very simple .when v consider them in pairs like 51-53,159-161 , the difference is two. so the prev. pair shd b 15-17.
• 13 years agoHelpfull: Yes(1) No(0)