M4maths Previous Puzzles

10 Aug 2022 Average

Average score of a group of athletes was 42 in certain event. When a new athlete join a group and scores equal to 250% of the average score of a group, then average of a group increases by 30%. How many athletes were there in a group before joining of a new athlete ?

OPtion

1) 4
2) 3
3) 6
4) 7
5) 9
6) 2
7) 5
8) 8
9) 10
10) None of these

Solution

Before joining new athlete, let there were 'x' athletes, so their total score = 42x
Score of a new athlete = (250/100)*42 = 105
New average = (42x + 105) / (x+1) = (130/100)*42
42x + 105 = (x+1)*54.6
12.6x = 50.4
x = 4
.'. There were 4 athletes before joining of a new athlete.
Correct Option 1)

Correct Option: 1 Best Solution (4)

Dr.Dipin Singh   2 years AGO

42x+42*2.5 = (x+1)*(42*1.3)
x=4

Like? Yes (1) | No   

Pargat Pal Singh   2 years AGO

Extra scores above average of new member =150%
Increase in average scores=30%
Final no. of athletes =150/30= 5
Earlier athletes =4
So final

Like? Yes (1) | No (1)  

G.S.Kantharao   2 years AGO

Let x be the number of Athletes.
Average of x=42
Sum=42x
After joining increased by 30%=54.6
Sum=54.6(x+1)=54.6x+54.6
Now
54.6x+54.6-42x
=42*250%=105
12.6x=105-54.6=50.4
x=4
My option is 1👈

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RAMADURAI NATESAN   2 years AGO

Let n be initial no.in group. It is given that
42n + (2.5) *42 = (n+1)*1.3 * 42.Solving, n = 4

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