logo

CuriousTab

CuriousTab

Discussion


Home Aptitude Linear Equation See What Others Are Saying!
  • Question
  • If the number obtained on the interchanging the digits of two-digits number is 18 more than the original number and the sum of the digits is 8, then what is the original number?


  • Options
  • A. 50
  • B. 51
  • C. 35
  • D. 53

  • Correct Answer
  • 35 

    Explanation

    Method 1 to solve the given question.
    Lets assume the unit's digit is y and the ten's digit is x. then, the number is 10 x + y.
    According to question, after interchanging the digits, the new number is 10y + x.
    Then,
    New Number - 18 = Original number
    10y + x = 10x + y + 18
    ? 9y - 9x = 18
    ? y - x = 2 .....................(1)
    Again according to question,
    Sum of digits of Original Number = 8
    x + y = 8 ..............................(2)
    Add the equation (1) and (2) , we will get
    y - x + x + y = 2 + 8
    ? 2y = 10
    ? y = 5
    Put the value of Y in equation (2) , we will get
    x + 5 = 8
    ? x = 8 - 5 = 3
    Then , the original number = 10x + y
    Put the value of x and y and get the original number.
    The original number = 10x + y = 10 x 3 + 5 = 30 + 5 = 35

    Method 2 to solve the given question.
    Given that sum of digits of original number is 8.
    Let us assume that unit digit is x , then ten digit will be 8 - x. (since sum of digits is 8.)
    Now Original number = 10( 8 - x) + x
    After interchanging the digits , the number = 10x + (8 - x) = 9x + 8
    According to question.
    New number = original number + 18
    ? 9x + 8 = 10(8 - x) + x + 18
    ? 9x + 8 = 80 - 10x + x + 18
    ? 9x + 8 = 98 - 9x
    ? 9x + 9x = 98 - 8
    ? 18x = 90
    ? x = 90/18
    ? x = 5
    The original number = 10(8 - x) + x = 10(8 - 5) + 5 = 10(3) + 5 = 30 + 5 = 35


  • More questions

    • 1. A bag contains 25 paise, 50 paise and 1 Rs coins. There are 220 coinsinall and the total amount in the bag is Rs. 160. If there arethrice as many 1 Rs. coins as there are 25 paise coins, then what is the number of 50 paise coins?

    • Options
    • A. 60
    • B. 40
    • C. 120
    • D. 80
    • Discuss
    • 2. Simplify : 69 X 69 X 69 -65 X 65 X 669 X 69 + 69 X 65 + 65 X 65

    • Options
    • A. 1
    • B. 4
    • C. 0.216
    • D. 0.164
    • Discuss
    • 3. If a+bab=21 , then the value of (a-b) is

    • Options
    • A. 1
    • B. 0
    • C. -1
    • D. 2
    • Discuss
    • 4. If x = 1 + ?2 + ?3, then the value of x2-2x-4=0

    • Options
    • A. ?6
    • B. 2?3
    • C. 3?2
    • D. 2?6
    • Discuss
    • 5. If 2x-y2+(3y-2z)2=0, then the ratio of x:y:z is

    • Options
    • A. 1 : 3 : 2
    • B. 1 : 2 : 3
    • C. 3 : 1 : 2
    • D. 3 : 2 : 1
    • Discuss
    • 6. If (4a-3)2=0, then the value of 64a3+12a+13 is

    • Options
    • A. 0
    • B. 11
    • C. 22
    • D. 33
    • Discuss
    • 7. The value of cos220°+cos270° is

    • Options
    • A. 0
    • B. 1
    • C. 1/2
    • D. 13
    • Discuss
    • 8. If a=101 then the value of a(a2-3a+3) is

    • Options
    • A. 1000000
    • B. 1010101
    • C. 1000001
    • D. 999999
    • Discuss
    • 9. If x=2+3, then the value of x2-x+1x2+x+1 is

    • Options
    • A. 2/3
    • B. 3/4
    • C. 4/5
    • D. 3/5
    • Discuss
    • 10. In ?ABC, ?B=35°, ?C=65° and the bisector of ?BAC meets BC in D. Then ADB is

    • Options
    • A. 40°
    • B. 75°
    • C. 90°
    • D. 105°
    • Discuss


    Comments

    There are no comments.

Enter a new Comment