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Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average by 8 runs. His new average is:

A. 20

B. 21

C. 28

D. 32

Answer: Option C

Solution(By Examveda Team)

Let Ajit's average be x for 9 innings. So, Ajit scored 9x run in 9 innings.
In the 10th inning, he scored 100 runs then average became (x+8). And he scored (x + 8) × 10 runs in 10 innings.
Now,
$$\eqalign{ & \Rightarrow 9x + 100 = 10 \times \left( {x + 8} \right) \cr & {\text{or}},\,9x + 100 = 10x + 80 \cr & {\text{or}},\,x = 100 - 80 \cr & {\text{or}},\,x = 20 \cr & {\text{New}}\,{\text{average}} = \left( {x + 8} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 28\,{\text{runs}} \cr} $$

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Comments ( 19 )

  1. Sujith Kumar
    Sujith Kumar :
    2 months ago

    Ok, Good.., But when student doing competitive exams we they short cut method, plz explain in short cut methods

  2. Irfan Khan
    Irfan Khan :
    3 months ago

    It's the so best learning website to improve mathematical calculation

  3. Salimreza Jim
    Salimreza Jim :
    4 months ago

    100-(8*9)=28

  4. Fardhus Sharker
    Fardhus Sharker :
    11 months ago

    Good

  5. Ashraful Islam
    Ashraful Islam :
    1 year ago

    Let, initial average = x
    Acq,
    10(x+8)-9x = 100
    x = 100-80 = 20
    New average = 20+8 = 28

  6. Ilaks ..
    Ilaks .. :
    2 years ago

    thanks

  7. Anju Napit
    Anju Napit :
    2 years ago

    thanks

  8. Lakshmi Kancharana
    Lakshmi Kancharana :
    2 years ago

    Good and clear explanation

  9. Sudhakar Prajapati
    Sudhakar Prajapati :
    2 years ago

    Good Solutions

  10. D Luffy
    D Luffy :
    2 years ago

    Didn't get it.

  11. Sarthak Jain
    Sarthak Jain :
    3 years ago

    Let Ajit's average be x for 9 innings. So, Ajit scored 9x run in 9 innings.
    In the 10th inning, he scored 100 runs then average became (x+8). And he scored (x+8)*10 runs in 10 innings.
    (9x+100)/10 = x+8 (since in 10th inning, 100 more then 9th inning and average gets increses by 8)
    therefore on solving this equation we get ,
    x=20
    But the new average is increased by 8 runs
    therefore x+8 i.e 20+8 = 28..

  12. Shivani Burman
    Shivani Burman :
    3 years ago

    Nice solution

  13. Bhartika Singh
    Bhartika Singh :
    3 years ago

    Can't understand

  14. Akbar Hajj
    Akbar Hajj :
    3 years ago

    c

  15. Ravi Kumar
    Ravi Kumar :
    3 years ago

    28

  16. Gopal Nayak
    Gopal Nayak :
    4 years ago

    Best questions

  17. Saltaf
    Saltaf :
    5 years ago

    c

  18. Rahul Jaiswal
    Rahul Jaiswal :
    5 years ago

    Its 28

  19. Sanjeevinaidu
    Sanjeevinaidu :
    5 years ago

    28

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