model 7 marks scored in examinations Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (c)

Let the total number of candidates = x

Number of candidates passed in English = 0.6x

Number of candidates passed in Maths = 0.7x

Number of candidates failed in both subjects = 0.2x

Number of candidates passed in atleast one subject

= x – 0.2x = 0.8x

0.6 x + 0.7x – 2500 = 0.8 x

1.3x – 0.8x = 2500

0.5x = 2500 ⇒ $x = 2500/0.5 = 5000$

Answer: (a)

Let the number of students in the class be 100.

Number of students in Biology = 72 and number of students in Maths = 44.

Number of students opting for both subjects = 72 + 44 – 100 = 16

Since, When 16 students opt for both subjects, total number of students = 100

When 40 students opt for both subjects,

total number of students = $100/16 × 40$ = 250

Answer: (b)

46% of 500 = ${500 × 46}/100 = 230$

32% of 300 = ${300 × 32}/100 = 96$

Required marks = 230 – 96 = 134

Let x% of 200 = 134

${200 × x}/100 = 134$

2x = 134 ⇒ x = $134/2$ = 67%

Answer: (b)

Let maximum marks be x, then,

${36 × x}/100 = 113 + 85 = 198$

$x = {198 × 100}/36 = 550$

Using Rule 24,

a = 36%, b = 113, c = 85

Maximum marks = ${(b + c)}/a × 100$

= ${(113 + 85)}/36 × 100$

= $198/36 × 100$ = 550

Answer: (a)

Let the total marks be x.

According to the question,

25% of x + 40 = 33% of x

(33 – 25)% of x = 40

8% of x = 40

x = ${40 × 100}/8$ = 500

Answer: (a)

Total candidates = 1000 + 800 = 1800

The candidates who are passed

= $1000 × 60/100 + 800 × 50/100$

= 600 + 400 = 1000

The number of candidates who failed = 1800 – 1000 = 800

Required percent = $800/1800 × 100 = 44.4%$

Using Rule 25,

Percentage of passed students = $({B.b + G.g}/{B + G})%$

= ${1000 × 60 + 800 × 50}/{1000 + 800}$

= ${60000 + 40000}/1800$

= $100000/1800 = 500/9 = 55.5$

Percentage of failed students = 100 – 55.5 = 44.4%