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

Answer: (c)

Failed candidates = ${1100 × 50}/100 + {900 × 60}/100$

= 550 + 540 = 1090

Required percentage = $1090/2000 × 100 = 54.5%$

Using Rule 25,

B = 1100, b = 50%, G = 900, g = 40%

Percentage of failed candidates = ${(Bb + Gg)}/{B + G}%$

= ${1100 × 50 + 900 × 40}/{1100 + 900}$

= ${55000 + 36000}/2000$

= $91/2$ = 45.5%

Answer: (d)

Number of students passed in first year = 75

Number of students passed in second year

= ${60 × 75}/100 = 45$

Total number of passed students = 75+45=120

Total number of appeared students =175

∴ Required percentage

= $120/175 × 100 = 68{4}/7%$

Answer: (d)

The percentage of students who pass in one or two or both subjects

= 60 + 70 – 40 = 90

Percentage of failed students = 100 – 90 = 10%

Answer: (a)

Let total number of students = 100

Number of failures in Maths = 34

Number of failures in English = 42

Number of failures in both subjects = 20

Number of failures in Maths or English or both

= 34 + 42 – 20 = 56

Number of students who passed in both subjects

= 100 – 56 = 44

The required percentage = 44%

Using Rule 23,

a = 34%, b = 42%, c = 20%

Passed candidates in both the subjects

= 100 – (a + b – c)

= 100 – (34 + 42 – 20) = 100 – 56 = 44%

Answer: (d)

Let marks obtained by Supriyo = x

${9x}/10 = 81 ⇒ x = {81 × 10}/9 = 90$

Answer: (b)

Successful boys in English or Maths or both

= 80 + 85 – 75 = 90%

Unsuccessful boys = 10%

Total number of boys = $100/10 × 45$ = 450