ERJ Brainteaser: August
30 Aug 2024
For some great answering, including supplying the only correct reply to extra tricky Q1, it’s congratulations to Michele Girardi of Mastaf SpA, our new Brainiac of the Month
Question 4: You cannot be series XXI
23, 57, 1113, _?_ ...
Answer: These are sequential pairs of prime numbers, so the next number in this series would be 1719, then 2329 etc. Very well done to: John Bowen, consultant, Bromsgrove, UK; Stephan Paischer, head of product management and market intelligence, Semperit AG Holding, Vienna, Austria; Kamila Staszewska, R&D / quality lead, Abcon Industrial Products Ltd, Cootehill, Co. Cavan, Ireland; Michele Girardi, quality manager, Scame Mastaf SpA, Suisio, Italy; Sudi Sudarshan, principal consultant, Global Mobility Strategies, USA; and everyone else who had a go.
Question 3: High five
Fill in the blanks using +, -, *, or / to make this equation valid. You may also add parentheses if necessary.
5 _ 5 _ 5 _ 5 _ 5 = 24
Answer: Readers came up with a nice variety of answers to this question (see Solutions below). Very well done to: Simon Winfield, director, MacLellan Rubber Ltd, Wednesfield, Wolverhampton, UK; Kamila Staszewska, R&D / quality lead, Abcon Industrial Products Ltd, Cootehill, Co. Cavan, Ireland; Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; Kate Burns, senior technologist and regulatory officer, Prisma Colour Ltd, Birch Vale, High Peak, Derbyshire; Sabit Karayel, compound development manager, Petlas Lastik Sanayi ve Ticaret A?, Türkiye; Michele Girardi, quality manager, Scame Mastaf SpA, Suisio, Italy; Semih Öngir, maintenance manager, Petlas Lastik Sanayi ve Ticaret A?, Türkiye.
An extra and exceptional well done to Michele Girardi, who cleverly deduced the answer to Q1 - one of our toughest ever teasers: The missing number is 47. The series is 29, 30, 50; 47; 47, 79. Referring to sports and Olympics: The bronze medals are made of Copper, Tin and Zinc, whose atomic numbers are 29,30,50; the Silver medals are made of Silver whose atomic number is 47; and the Gold medals are made of Silver plated with Gold, whose atomic numbers are 47 and 79.
SOLUTIONS
Simon Winfield
5 x 5 x 5 – 5 / 5 = 24
5 x 5 x 5 = 125 – 5 = 120 / 5 = 24
Kamila Staszewska
The answer can be: (5 * 5 * 5 - 5) / 5 = 24
Andrew Knox
Answer: ((5*5*5)-5)/5=24
Dr Kate Burns
[(5*5*5)-5]/5
= (125 -5)/5
=120/5
=24
Sabit Karayel
((5*5*5)-5)/5=24
Michele Girardi
(5x5x5 -5 )/5 = 24
Semih Öngir
5*(5-(5/5)/5)=24
Question 2: Millennium bug
Fill in the missing years in this millennium sequence:
2307, 2417, 2527, 2637, _, _, _.
Answer: The rest of the sequence is: 2747, 2857, 2967 (add110), as neatly worked out by: Andrew Knox, Rubbond International, Ohé en Laak, The Netherlands; John Bowen, consultant, Bromsgrove, UK; Sabit Karayel, compound development manager, Petlas Lastik, Saniya ve Ticaret AS, Turkey; Michele Girardi, quality manager, Scame Mastaf SpA, Suisio, Italy; Sudi Sudarshan, principal consultant, Global Mobility Strategies, USA. Well done to all and everyone else who had a go.
(ps The new clue added to Q1 might help to reveal the answer)
Question 1: Tricky teaser
Complete the series
29, 30, 50; 47; ?, 79.
Clues: Sport, ----fish, Bronze...
Email your answer: correct replies next Friday*.
*As this teaser proved even trickier than we imagined, we'll run as a bonus question until we get a few correct answers - hopefully.
