model 11 percentage with ratios Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (d)

Let the numbers be 2x and 3x.

According to the question,$(20/100 × 2x) + 20$

= $(10/100 × 3x) + 25$

${2x}/5 + 20 = {3x}/10 + 25$

${2x}/5 - {3x}/10$ = 25 - 20

${4x - 3x}/10$ = 5 ⇒ x = 50

The smaller number = 2x = 100

Answer: (b)

30% of A = 25% of B

30 A = 25 B

A : B = 25 : 30 = 5 : 6

Again, 25% of B = 20% of C

25 B = 20C ⇒ 5B = 4C

B : C = 4 : 5

A : B : C = 5 × 4 : 4 × 6 : 6 × 5

= 20 : 24 : 30 = 10 : 12 : 15

Answer: (c)

According to the question, A × 35% = B × 25%

$A/B = 25/35 = 5/7$

Answer: (a)

The raised price = $120/100$ of the former price

The householder must now consume $100/120$ of the original amount

The reduction in consumption = $(1 – 100/120)$ of the original consumption = $1/6$ of the original consumption

i.e. 1 : 6

Required percentage = $(20/{100 + 20})×100$

= $20/120×100$ = $100/6$%

Required ratio = 1 : 6

Answer: (a)

Let the numbers be x and y and x is greater than y.

Then x – y = 45% of (x + y)

x – y = $45/100(x + y)$

x – y = $9/20(x + y)$

20x – 20y = 9x + 9y

20x – 9x = 20y + 9y

11x = 29y

$x/y = 29/11$ or 29 : 11

Answer: (c)

Let the number of students in school be 100.

Boys ⇒ 60 Girls ⇒ 40

Students who do not hold scholarship :

Boys ⇒ ${60 × 80}/100$ = 48 Girls ⇒ ${40 × 75}/100$ = 30

Required answer = 48 + 30 = 78 i.e., 78%