Question

Of the candidates in an examination, 40% were girls, 75% of the boys and 70% of the
girls passed and 120 girls got plucked. Find how many boys failed.
(Ans.: 150 boys failed)


plz give explained ans. ty
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Answer 1

Step-by-step explanation:

Total number of students = 480

Percentage of total students passed

= 75 % of total student = 75×480100=360students

Now, using the condition from the question,

Let the number of boys be x

Then, 70% of x + 85% of (480 - x) = 360

=> 70×x100+85×(480−x)100=360

=> 70x - 85x + 40800 = 36000

=> 40800 - 36000 = 85x - 70x

=> 4800 = 15x

=> x=480015=320

There are 320 boys who have appeared for the examination.

please mark it as brainliest answer

Answer 2

Answer:

Solution :

Total number of students = 480

Percentage of total students passed =75%

Thus no. of students passed = 75 % of total student

$</p><p> = \frac{75}{100} *480 </p><p>100$

$=\: 360{ \tt{students}}$

Let the number of boys be x

Then no. of girls will be total students - no. of boys= 480-x

Since 360 students got passed out which 70 % were boys and 85% were girls

Then, 70% of x + 85% of (480 - x) = 360

$=>\frac{70}{100} x+\frac{85}{100}(480−x)=360$

$=>70x+85*(480-x) =3600$

$⇒70x - 85x + 40800 = 36000$

$⇒40800 - 36000 = 85x - 70x$

$=> 4800 = 15x$

=> x=4800/15=320

There are 320 boys who have appeared for the examination