Question

1)Mean marks of Salim in 5 subjects is 78. He got 76, 78, 80 and 77 marks respectively in English, Maths , Science, Social science marks. How many marks did Salim get in Hindi? 
1)75
2)79
3)82
4)84​

Answer 1

Answer:

Mean is same as Average. So,

Sum of Numbers

Average = -----------------------------------

Total Numbers

Let x be the marks Salim got in Hindi

= 76 + 78 + 80 + 77 + x

--------------------------------- = 78

5

311 + x/5 = 78

(Transversing of 5 to RHS)

311 + x = 78 × 5

311 + x = 390

(Transversing of 311 to RHS)

x = 390 - 311

x = 79

So, Salim got 79 marks in Hindi

Checking

76 + 78 + 80 + 77 + 79/5

= 390/5

= 78

So, the answer is Correct

Answer 2

Salim got 79 marks in Hindi if Mean marks of Salim in 5 subjects is 78 and he got 76, 78, 80 and 77 marks respectively in English, Maths, Science, Social science marks

Given:

• Mean marks of Salim in 5 subjects is 78.
• Salim got 76, 78, 80 and 77 marks respectively in English, Maths , Science, Social science marks.

To Find:

• Salim marks in Hindi

Solution:

$\text{Mean}=\dfrac{\text{sum of all the obervations}}{\text{number of the observations}}$

Step 1:

Calculate Total marks by multiplying mean marks with number of subjects.

Total Marks in 5 Subjects = 78 x 5

=> Total Marks in 5 Subjects = 390

Step 2:

Add Marks of  English, Maths , Science, Social science  subjects

Total Marks in 4 Subjects = 76 + 78 + 80 + 77

Total Marks in 4 Subjects = 311

Step 3:

Subtract Marks in 4 subjects ( except Hindi) from Marks in 5 subjects to get marks in Hindi

390 - 311

= 79

Hence,  Salim got 79 marks in Hindi

Correct option is 2) 79