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

Answer: (d)

Boys = 30, Girls = 20 (let)

Boys getting no scholarship = 24

Girls getting no scholarship = 15

Sum = 24 + 15 = 39

Required percentage = $39/50 × 100$ = 78%

Answer: (c)

Let Rama's expenditure = 5x

Savings = 3x

Rama's income = 5x + 3x = 8x

After increase,

Rama's income = $112/100 × 8x = 8.96 x$

Rama's expenditure = ${5x × 115}/100 = 5.75x$

Rama's savings = (8.96x – 5.75x) = 3.21x

Rama's saving percent = $({3.21x - 3x}/{3x})×100$

= $0.21/3 × 100 = 7$

Answer: (c)

Let number of boys be x.

Then, $x + 120/100x = 66 ⇒ x + {6x}/5 = 66$

${5x + 6x}/5 = 66 ⇒ x = {66 × 5}/11 = 30$

Number of girls = 66 - 30 = 36

New ratio = 30 : (36 + 4) = 30 : 40 = 3 : 4

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: (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: (c)

Boys in the village = 3x

Girls in the village = 2x

Villagers who appeared in the examination

= ${3x × 30}/100 + {2x × 70}/100$

= ${9x}/10 + {14x}/10 = {23x}/10$

Villagers who did not appear in the examination

= ${3x × 70}/100 + {2x × 30}/100$

= ${21x}/10 + {6x}/10 = {27x}/10$

Required ratio = ${23x}/10 : {27x}/10$ = 23 : 27