Question

Anamika obtained average 126 marks in 5 subjects. she obtained 100. and 87 marks in the sixth and seventh subject respectively.what is her average marks in all 7 subjects

Answer 1

Answer:

The new average is 116.7

Step-by-step explanation:

Given :

Average = 126 marks

In subjects = 5

Marks in other 2 subjects = 100 and 87

To find :

Her average in 7 subjects

Solution :

★ Sum of marks of her 5 subjects -

$\sf{\longrightarrow} \: 126 \times 5 \\ \\ \sf{\longrightarrow} \: 630$

Total marks of 5 subjects = 630

$\rule{300}{1}$

★ Add the new observations -

New observations = 100 and 87

$\sf{\longrightarrow} \: 630 + (100 + 87) \\ \\ \sf{\longrightarrow} \: 630 + 187 \\ \\ \sf{\longrightarrow} \: 817$

$\rule{300}{1}$

★ New average -

• Sum of observations = 817
• Number of observations = 7

$\boxed{\sf{Mean = \frac{Sum \: of \: Observations}{No. \: of \: Observations}}}$

$\sf{\longrightarrow} \: Mean = \dfrac{817}{7} \\ \\ \sf{\longrightarrow} \: Mean = 116.7 \: \: (approx)$

Mean = 116.7 (Approx)

$\therefore$ The new average is 116.7

Answer 2

Answer:

$\large{\underline{\boxed{\mathfrak\green{Average \: marks \: in \: 7 \: subjects = 116.71 }}}}$

$\rule{100}{2}$

Given:-

• Average marks in 5 subjects = 126 marks.

• Marks in 6th subject = 100

• Marks in 7th subject = 87

To find:-

• Average marks in 7 subjects = ?

$\rm We \: know, \\\\\dag \: \: {\boxed{\rm{Average \: marks = \dfrac{Total\: marks}{Number \: of \: Subjects} }}}$

$\dashrightarrow\sf Total \: marks = Average \: marks \times Number\: of\: subjects \\\\\sf In\: first\: 5\: subjects:- \\\\\dashrightarrow\sf Total \: marks = 126 \times 5 \\\\\dashrightarrow\sf Total \: marks = \large{\boxed{\sf\green{630}}}$

$\sf Now,total \: marks \: in \: 7 \: subjects :- \\\\\dashrightarrow\sf Total \: marks = 630 + 100 + 87 \\\\\dashrightarrow\large{\underline{\boxed{\sf\blue{Total \: marks = 817 }}}}$

$\sf Now, \\\\\dashrightarrow\sf Average \: marks = \dfrac{817}{7} \\\\\dashrightarrow\large{\underline{\boxed{\sf\green{Average \: marks = 116.71 }}}}$

$\therefore{\underline{\text{Average \: marks \: obtained = 116.71 }}}$

$\rule{200}{1}$