?
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:
Answer & Solution
Correct Answer:
Option
C
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,
$$\eqalign{ & \Rightarrow 9x + 100 = 10 \times \left( {x + 8} \right) \cr & {\text{or}},\,9x + 100 = 10x + 80 \cr & {\text{or}},\,x = 100 - 80 \cr & {\text{or}},\,x = 20 \cr & {\text{New}}\,{\text{average}} = \left( {x + 8} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 28\,{\text{runs}} \cr} $$
In the 10th inning, he scored 100 runs then average became (x+8). And he scored (x + 8) × 10 runs in 10 innings.
Now,
$$\eqalign{ & \Rightarrow 9x + 100 = 10 \times \left( {x + 8} \right) \cr & {\text{or}},\,9x + 100 = 10x + 80 \cr & {\text{or}},\,x = 100 - 80 \cr & {\text{or}},\,x = 20 \cr & {\text{New}}\,{\text{average}} = \left( {x + 8} \right) \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 28\,{\text{runs}} \cr} $$
Join the Discussion
Login to post a comment or share your explanation.
Login100-72 = 28 ans new avg
For 9th inning
x = T/9
9x=T
For 10th inning
x+8=T/10
10(x+8)=T
9x+100=10(x+8)
9x+100=10x+80
x=20
New Average:x+8=28
_____________________________________
Shortcut:
Innings×increasing runs=Answer
Then, Runs-Answer=New Average
9×8=72
Then, 100-72=28
New Average:28
100-80 =20
New increment = 20+8
Assume Till 9th inng his avg will be x
In 10th inng his score was 100 and his total avg increase by x+8
I.e for previous 9 innengs 8 will be given to each inngs
So 9*8 = 72 and for 10th inng it's already 100 so
100-72=28
100-72=28
100-(8*9)=28
Nice Sir
Acq,
10(x+8)-9x = 100
x = 100-80 = 20
New average = 20+8 = 28
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..