Exercise :: Problems on Numbers  General Questions
 Problems on Numbers  Important Formulas
 Problems on Numbers  General Questions
 Problems on Numbers  Data Sufficiency 1
 Problems on Numbers  Data Sufficiency 2
1.  If onethird of onefourth of a number is 15, then threetenth of that number is: 

Answer: Option D Explanation: Let the number be x.

2.  Three times the first of three consecutive odd integers is 3 more than twice the third. The third integer is: 

Answer: Option D Explanation: Let the three integers be x, x + 2 and x + 4. Then, 3x = 2(x + 4) + 3 x = 11. Third integer = x + 4 = 15. 
3.  The difference between a twodigit number and the number obtained by interchanging the positions of its digits is 36. What is the difference between the two digits of that number? 

Answer: Option B Explanation: Let the ten's digit be x and unit's digit be y. Then, (10x + y)  (10y + x) = 36 9(x  y) = 36 x  y = 4. 
4.  The difference between a twodigit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ? 

Answer: Option B Explanation: Since the number is greater than the number obtained on reversing the digits, so the ten's digit is greater than the unit's digit. Let ten's and unit's digits be 2x and x respectively. Then, (10 x 2x + x)  (10x + 2x) = 36 9x = 36 x = 4. Required difference = (2x + x)  (2x  x) = 2x = 8. 
5.  A twodigit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is: 

Answer: Option B Explanation:
10x^{2} + 8 + 18x = 80 + x^{2} 9x^{2} + 18x  72 = 0 x^{2} + 2x  8 = 0 (x + 4)(x  2) = 0 x = 2. 