Question

(ii) In a class test, Ramesh and Suresh obtained 18 and 12 marks respectively out of 40. If the average of the marks obtained by Ramesh, Suresh and Radhika is 21. find the marks obtained by Radhika.​

Answer 1

Marks obtained by Radhika = 33

Step-by-step explanation:

Given :-

In a class test, Ramesh and Suresh obtained 18 and 12 marks respectively out of 40. The average of the marks obtained by Ramesh, Suresh and Radhika is 21.

To find :-

Find the marks obtained by Radhika?

Solution:-

Given that

Total marks in a class test = 40

Marks obtained by Ramesh = 18

Marks obtained by Suresh = 12

Let the marks obtained by Radhika be X

Total marks of Ramesh , Suresh and Radhika

=> 18+12+X

=> 30+X

Number of people = 3

We know that

Average = Sum of all observations/ Number of all observations

=> Average marks of them

=> (30+X)/3

According to the given problem

Average marks of the three people = 21

=> (30+X)/3 = 21

=> 30+X = 21×3

=> 30+X = 63

=> X = 63-30

=> X = 33

Marks of Radhika = 33

Answer :-

Marks obtained by Radhika in the class test = 33

Check:-

Marks of Ramesh = 18

Marks of Suresh = 12

Marks of Radhika = 33

Average mark of them = (18+12+33)/3

=> 63/3

=> 21

Verified the given relations in the given problem.

Used formulae:-

Average = Sum of all observations/ Number of all observations

Answer 2

Question

In a class test, Ramesh and Suresh obtained 18 and 12 marks respectively out of 40. If the average of the marks obtained by Ramesh, Suresh and Radhika is 21. find the marks obtained by Radhika.​

Answer:

Marks obtained by Radhika is 33.

Step-by-step explanation:

Total marks=40

Marks obtained by Ramesh=18

Marks obtained by Suresh=12

let assume Marks obtained by Radhika as

(Average=sum of observation/ no. of observation)

=> (18+12+x)/3=21

=>(30+x)/3=21

=>30+x=21×3

=>30+x=63

=>x=63-30

=>x=33

Conclusion:

Hope this helps you.