Question

Out of 1000 students in a school, 600 are boys
and the rest are girls. If 30% of the boys and
20% of the girls like Maths, find the following.
(i) How many students in all like Maths?
(ii) What per cent of total number of students
like Maths?​

Answer 1

Answer

• Total students who like maths = 260.
• Percentage of students who like maths = 26%.

Given

• Total number of students = 1000.
• Number of boys = 600.
• Percentage of boys who like maths = 30%.
• Percentage of gírls who like maths = 20%.

To Find

• How many students in all like maths.
• Percentage of total number of students like maths.

Step By Step Explanation

Total number of students = Number of boys + Number of gírls.

1000 = 600 + Number of gírls.

400 = Number of gírls.

Now,

Total number of students who like maths = Number of boys who like maths + Number of gírls who like maths.

Total number of students who like maths = 30% of 600 + 20% of 400.

Number of boys ⤵

$\longmapsto \sf \cfrac{ \cancel{600}}{ \cancel{100}} \times 30 \\ \\\longmapsto \sf 6 \times 30 \implies{ \bold{ \red{180}}}$

Number of girls ⤵

$\longmapsto \sf \cfrac{ \cancel{400}}{ \cancel{100}} \times 20 \\ \\\longmapsto \sf 4 \times 20 \implies{ \bold{ \purple{80}}}$

Therefore, the total number of students who like maths = 180 + 80 => 260.

Now,

Percentage of students who like maths will be ⤵

$\underline{\boxed{\bold{ \cfrac{Students \: who \: like \: Maths}{Total \: Students} \times100}}}$

By substituting the values :

$\longmapsto \sf \cfrac{26 \cancel0}{ \cancel{1000}} \times \cancel{100} \\ \\ \longmapsto \bold \green{ 26\%} \: \: \bigstar$

Therefore, percentage of students who like maths = 26%.

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