Showing posts with label Number Theory. Show all posts
Showing posts with label Number Theory. Show all posts

Sunday, October 9, 2011

Problem of the Day 9th Oct 2011


In an increasing Arithmetic Progression, the product of the 5th term and the 6th term is 300. When
the 9th term of this A.P. is divided by the 5th term, the quotient is 5 and the remainder is 4. What is
the first term of the A.P.?
(a) 12                 (b) –40               (c) –16                     (d) –5

Friday, October 7, 2011

Problem of the Day 6th Oct 2011


If xΔ(y +1) = yΔ(x +1), xΔ x = 1 and (x − y)Δ(x + y) = xΔ y, then what is the value of 1001Δ1?
(a) 1000                   (b) 100                    (c) 10                 (d) 1

Tuesday, October 4, 2011

Problem of the Day 4th Oct 2011

Find x and y, where the variables are natural numbers:

\frac{xy + y}{x + y} = \frac{15}{7}
\frac{x^2 + y}{2x + y} = \frac{19}{11}

Monday, October 3, 2011

Problem of the Day 3rd Oct 2011

How many ordered pairs of positive integers (m, n) satisfy the system

\begin{align*}\gcd (m^3, n^2) & = 2^2 \cdot 3^2,\\ \text{LCM} [m^2, n^3] & = 2^4 \cdot 3^4 \cdot 5^6,\end{align*}

where \gcd(a, b) and \text{LCM}[a, b] denote the greatest common divisor and least common multiple of a and b, respectively?



(A)   0        (B) 1         (C)  2            (3) More than 2

Sunday, October 2, 2011

Problem of The day 2nd Oct 2011

Let [x] and {x} respectively denote the integer and fractional part of of a real number x. If {n} + {3n}=1.4, find the sum of all possible values of 100{n}.

(A) 180           (B) 145                (C) 85      (d) 102

Friday, September 30, 2011

Wednesday, September 28, 2011

Problem of the Day 28 Sept 2011


A good approximation of π is 3.14. Find the least positive integer d such that if the area of a circle with
diameter d is calculated using the approximation 3.14, the error will exceed 1.


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Tuesday, September 27, 2011

Problem of the Day 27 Sept 2011


The diagram below shows some small squares each with area 3 enclosed inside a larger square. Squares that touch each other do so with the corner of one square coinciding with the midpoint of a side of the other square. Find integer n such that the area of the shaded region inside the larger square but outside the smaller squares is n



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Monday, September 26, 2011

Problem of the day 26 Sept 2011


Let a1= 2 and an+1 = 2an + 1. Find the least value of an which is not prime.
(a) 47                  (b) 4                    (c) 5                 (d) 95





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Wednesday, September 21, 2011

Problem of the Week 21 Sept 2011

The leftmost digit of an integer of length 2000 digits is 3. In this integer, any two consecutive digits must be divisible by 17 or 23. The 2000th digit may be either a or b. What is the value of a+b?



Tuesday, September 13, 2011

Problem of the Day 13 Sept 2011

Let X be the set of three digit prime numbers with the following properties: 1) Each digit of the elements of X are distinct. 2) Each digit of the elements of X are prime. Let K be the sum of all the elements of X. Find the sum of the digits of K?




Thursday, August 6, 2009

Problem of The day 06.08.09

1. Four digits of the number 29138576 are omitted so that the result is as large as possible. The largest omitted digit is (A) 9 (B) 8 (C) 7 (D) 6 (E) 5

Thursday, July 30, 2009

Problem of the Day 30.07.09

Find the sum of the digits of the least natural number N, such that the sum of the cubes of the four smallest distinct divisors of N is 2N?



1)  9                                2) 8                             3) 7                    4) 6                      5) 10

Monday, July 27, 2009

Problem of the day 27.07.09

Find the number of quadratic polynomials ax² + bx + c such that:

a) a, b, c are distinct.

b) a, b, c ε {1, 2, 3, ...2008}

c) x + 1 divides ax² + bx + c
a) 2013018            b) 2013021            c) 2014024             d) 2018040       e) none of these

Thursday, July 16, 2009

Bonus Question 16.07.09

Find the number of solutions in distinct positive  integers of x^4+y^4=z^4

A) 0                 B) 1                  C) 2                         D) 3                E) More than 3

Problem of the day 16.7.09

What is the sum of the digits of a two digit number which is 32 less than the square of the product of its digits?

A. 12                   B. 11                 C. 10 .                     D. 9                           E.      8

Tuesday, July 14, 2009

Problem of the day 14.7.09

Given that 1025/1024=1.0009765625, find the sum of the digits of 510?



(a)  36       (b) 40    (c) 50   (d) 102   (e) 41

Wednesday, July 8, 2009

Problems 8.07.09

I could not post due to some engagements. Here are a bunch of problems to compensate :)

Question 1)

A + B + C + D = D + E + F + G = G + H + I = 17 where each letter represent a number from 1 to 9. Find out number of ordered pairs (D,G) if letter A = 4.
a) 0                       b) 1                 c)2                        d) 3                 e) none of these

Question 2)

The sequence 1, 3, 4, 9, 10, 12..... includes all numbers that are a sum of one or more distinct powers of 3. Then the 50th term of the sequence is
a. 252                    b. 283                     c. 327                      d. 360                  e) none of these

Question 3)


Given that g(h(x)) = 2x² + 3x and h(g(x)) = x² + 4x − 4 for all
real x. WHich of the following could be the value of g(-4)?
a)1                     b) -1                          c) 2                 d) -2                   e) -3

Question 4)


If a, x, b and y are real numbers and ax+by = 4 and ax² +by² = 2 and
ax³ + by³= −3
then find (2x − 1)(2y − 1)
a)4                      b) 3                    c) 5                 d) -3          e) cannot be determined.

Question 5)


K1,K2,K3...K30 are thirty toffees. A child places these toffees on a circle, such that there are exactly n ( n is a positive integer) toffees placed between Ki and Ki+1 and no two toffees overlap each other. Find n
a)4                        b) 5                     c) 9                 d) 12                       e) 13

Question 6)
For the n found in previous  question, which of the two toffees are adjacently
placed on the circle? ( All other conditions remaining same)
a) K11 and K13                    b) K6 and K23                   c) K2 and K10              d) K11 and K18
e) K20 and K28

Friday, July 3, 2009

Problem Of The Day 04.07.2009

Let aabb be a 4-digit number (a≠0). How many such numbers are perfect squares?

A) 0   B) 1   C)  2   D) 3  E) 4