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

Answer: (d)

$x × 15/100 = y × 20/100$

x × 15 = y × 20

$x/y = 20/15 = 4/3$ = 4 : 3

Answer: (d)

Boys in school = 2x

Girls = 3x

Students who are not scholarship holders :

Boys ⇒ ${2x × 75}/100 = {6x}/4$

Girls ⇒ ${3x × 70}/100 = {21x}/10$

Total students who donot hold scholarship = ${6x}/4 + {21x}/10$

= ${30x + 42x}/20 = {72x}/20 = {18x}/5$

Required percentage = ${{18x}/5}/{5x} ×100$ = 72%

Answer: (b)

Let the number of boys and girls be 4x and x respectively.

Number of boys who hold scholarship. = $75/100 × 4x = 3x$

and number of girls who hold scholarship = ${70 × x}/100 = {7x}/10$

Number of students who do not hold scholarship

= $5x - 3x - {7x}/10 = 2x - {7x}/10$

= ${20x - 7x}/10 = {13x}/10$

The required percentage = ${{13x}/10}/{5x} × 100$

= ${13x}/{10 × 5x} × 100 = 26$%

Answer: (a)

Let the number of boys and girls in the college be 3x and 2x respectively.

Number of minor boys = $3x × 80/100 = {12x}/5$

Number of minor girls = $2x × 75/100 = {3x}/2$

Total number of minor students = ${12x}/5 + {3x}/2$

= ${24x + 15x}/10 = {39x}/10 $

Required percentage = ${39x}/{10 × 5x} × 100$ = 78%

(As total students = 3x + 2x)

Answer: (a)

7x – 5x = 200

2x = 200 ⇒ x = 100

Price of a pair of shoes

= 5x = 5 × 100 = Rs.500

Answer: (b)

${A × 60}/100 = B × 3/4$

A × $3/5 = B × 3/4$

$A/B = 3/4 × 5/3$ = 5 : 4