Quick Quiz on Number System

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Question 1

Vaibhav wrote a certain number of positive prime numbers on a piece of paper. Vikram wrote down the product of all the possible triplets among those numbers. For every pair of numbers written by viram, vishal wrote down down the corresponding GCD. If 90 of the numbers written by vishal are prime, how many numbers did vaibhav write?

• A6
• B8
• C10
• DCannot be dertimined

Question 2

A young girl counted in the following way on the fingers of her left hand. She started calling the thumb 1, the index finger 2, middle finger 3, ring finger 4, little finger 5, then reversed direction, calling the ring finger 6, middle finger 7, index finger 8, thumb 9, then back to the index finger for 10, middle finger for 11, and so on. She counted up to 1994. She ended on her.

• AThumb
• BIndex finger
• CMiddle finger
• DRing finger

Question 3

If a, b, c and d are four positive real number such that abcd = 1, what is the minimum value of (1 + a)(1 + b)(1 + c)(1 + d)

• A4
• B1
• C16
• D18

Question 4

Find the number of zeros in×××…………………

• A125
• B225
• C250
• D240
• E540

Question 5

For a positive integer n, let Pn denote the product of the digits of n and Sn denotes the sum of the digits on n. The number of integers between 10 and 1000 for which Pn + Sn = n is

• A81
• B16
• C18
• D9

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