__Must Solve DI for Bank/Insurance Exams (21 – 03 – 2018)__**Directions (1 – 5):**

**Given below is a table that represents the consumption and prices of electricity and water for four different houses. Based on this information, answer the questions that follow.**

**1. Suppose it is decided that all houses will be provided electricity at same price. What price should be kept so that the total amount of electricity bill generated for all four houses still remains same (in Rs. Per kWH)?**

a) 4.2

b) 4.425

c) 4.185

c) 4.35

e) 4.5

**2. By what percentage the bill of electricity for houses R and S together is less than bill of electricity for houses P and Q?**

a) 33.33%

b) 36.63%

c) 38.71%

d) 39.09%

e) 41.14%

**3. Which house will get the highest bill considering both electricity and water?**

a) P

b) Q

c) R

d) S

e) Cannot be determined

**4. At what price should water be sold to house Q so that its water bill is equal to total water bill of all other three houses (in Rs. Per kL)?**

a) 3.98

b) 4.06

c) 4.14

d) 4.42

e) 4.28

**5. What was the total electricity bill for houses P and R together?**

a) Rs. 1440

b) Rs. 1560

c) Rs. 1600

d) Rs. 1680

e) Rs. 1720

**Direction (6 – 10):**

**Below is given a pair of pie chart and bar graph representing number of students in different classes in a school in 2015 and growth in 2016. Based on this information, answer the questions that follow.**

**6. The students in 2016 in different classes are represented in a pie chart. What will be the difference between angles subtended by sectors representing 7th and 9th classes?(in°)**

a) 30

b) 36.24

c) 39.93

d) 45

e) 48.2

**7. If the increment in all the classes has only been in the form of girl students, then what will be the ratio of total number of boys and girls in 2016?**

a) 43 : 41

b) 23 : 27

c) 8 : 9

d) 2 : 3

e) Cannot be determined

**8. Instead of 20%, what should be the minimum growth in number of students for class 7th, so that it does not have minimum number of students in 2016?**

a) 41.12

b) 43.89

c) 46.67

d) 48

e) 49.52

**9. What will be the average number of students in classes 8th and 9th taken together in 2015 and 2016?**

a) 164

b) 171

c) 177

d) 183

e) 189

**10. What should be growth in number of students for class 8th in 2017 so that their number becomes same as number of students in class 9th in 2016?**

a) 10%

b) 12%

c) 15%

d) 8%

e) 7.5%

**Solutions:**

**1. B)**Electricity bill of a house = Consumption × Price

⇒ Electricity bill of a house P = Rs. 2 × 300 = Rs. 600

⇒ Electricity bill of a house Q = Rs. 6 × 450 = Rs. 2700

⇒ Electricity bill of a house R = Rs. 4 × 240 = Rs. 960

⇒ Electricity bill of a house S = Rs. 5 × 210 = Rs. 1050

Total bill for all four
houses = Rs. (600 + 2700 + 960 + 1050) = Rs. 5310

Suppose price is kept at
Rs. T per kWH.

Total electricity
consumption of four houses = (300 + 450 + 240 + 210) = 1200 kWH

⇒ 5310 = 1200T ⇒ T = 4.425

∴ Price should be kept at Rs. 4.425 per kWH.

**2. D)**Electricity bill of a house = Consumption × Price

⇒ Electricity bill of a houses P and Q = Rs. (2 × 300 + 6 × 450) = Rs. 3300

⇒ Electricity bill of a house R and S = Rs. (4 × 240 + 5 × 210) = Rs. 2010

∴ Percentage by which the bill of electricity for houses R and
S together is less than consumption of bill for houses P and Q = [(3300 – 2010)/3300] × 100 = 39.09%

**3. B)**Electricity bill of a house = Consumption × Price

⇒ Electricity bill of a house P = Rs. 2 × 300 = Rs. 600

⇒ Electricity bill of a house Q = Rs. 6 × 450 = Rs. 2700

⇒ Electricity bill of a house R = Rs. 4 × 240 = Rs. 960

⇒ Electricity bill of a house S = Rs. 5 × 210 = Rs. 1050

Water bill of a house =
Consumption × Price

⇒ Water bill of a house P = Rs. 3 × 60 = Rs. 180

⇒ Water bill of a house Q = Rs. 1 × 70 = Rs. 70

⇒ Water bill of a house R = Rs. 1 × 50 = Rs. 50

⇒ Water bill of a house P = Rs. 2 × 30 = Rs. 60

Total bills for houses P,
Q, R and S will be Rs. 780, Rs. 2770, Rs. 1010 and Rs. 1110, respectively.

Clearly, the bill is
highest for house Q.

**4. C)**Water bill of a house = Consumption × Price

Total water bill of
houses P, R and S = Rs. (3 × 60 + 1 × 50 + 2 × 30) = Rs. 290

∴ For house Q to have the same water bill, price = Rs.
290/consumption = Rs. (290/70) per kL = Rs. 4.14 per kL

**5. B)**Electricity bill of a house = Consumption × Price

⇒ Electricity bill of a house P = Rs. 2 × 300 = Rs. 600

⇒ Electricity bill of a house R = Rs. 4 × 240 = Rs. 960

∴ Total electricity bill for houses P and R together = Rs. 600
+ Rs. 960 = Rs. 1560

**6. B)**Number of students in class 6

^{th}in 2016 = 60 × (1 + 10/100) = 66

Number of students in
class 7

^{th}in 2016 = 45 × (1 + 20/100) = 54
Number of students in
class 8

^{th}in 2016 = 75 × (1 + 20/100) = 90
Number of students in
class 9

^{th}in 2016 = 90 × (1 + 10/100) = 99
Number of students in
class 10

^{th}in 2016 = 120 × (1 + 15/100) = 138
∴ difference between angles subtended by sectors representing
7

^{th}and 9^{th}classes = [(99 - 54)/(66 + 54 + 90 + 99 + 138)] × 360° = 36.24°**7. E)**We do not have the original distribution of boys and girls in 2015. So, actual ratio cannot be determined neither for 2015 and nor for 2016 after increment.

∴ Ratio cannot be uniquely determined.

**8. C)**Number of students in class 6

^{th}in 2016 = 60 × (1 + 10/100) = 66

Number of students in
class 7

^{th}in 2016 = 45 × (1 + 20/100) = 54
Number of students in
class 8

^{th}in 2016 = 75 × (1 + 20/100) = 90
Number of students in
class 9

^{th}in 2016 = 90 × (1 + 10/100) = 99
Number of students in
class 10

^{th}in 2016 = 120 × (1 + 15/100) = 138
To not have the minimum
value, number of students for class 7

^{th}should be more than 66.
∴ Minimum growth = [(66 - 45)/45] × 100 = 46.67%

**9. C)**Number of students in class 8

^{th}in 2016 = 75 × (1 + 20/100) = 90

Number of students in
class 9

^{th}in 2016 = 90 × (1 + 10/100) = 99
∴ average number of students in classes 8

^{th}and 9^{th}taken together in 2015 and 2016 ((75 + 90) + (90 + 99))/2 = 177**10. A)**Number of students in class 8

^{th}in 2016 = 75 × (1 + 20/100) = 90

Number of students in
class 9

^{th}in 2016 = 90 × (1 + 10/100) = 99
Suppose growth is T% for
class 8

^{th}students in 2017.
⇒ 90 × (1 + T/100) =
99

⇒ T = (99/90 - 1) × 100 = 10

∴ Growth should be 10%.