Must Solve DI for Bank/Insurance Exams (21 – 03 – 2018)

Mentor for Bank Exams

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 6th in 2016 = 60 × (1 + 10/100) = 66
Number of students in class 7th in 2016 = 45 × (1 + 20/100) = 54
Number of students in class 8th in 2016 = 75 × (1 + 20/100) = 90
Number of students in class 9th in 2016 = 90 × (1 + 10/100) = 99
Number of students in class 10th in 2016 = 120 × (1 + 15/100) = 138
difference between angles subtended by sectors representing 7th and 9thclasses = [(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 6th in 2016 = 60 × (1 + 10/100) = 66
Number of students in class 7th in 2016 = 45 × (1 + 20/100) = 54
Number of students in class 8th in 2016 = 75 × (1 + 20/100) = 90
Number of students in class 9th in 2016 = 90 × (1 + 10/100) = 99
Number of students in class 10th in 2016 = 120 × (1 + 15/100) = 138
To not have the minimum value, number of students for class 7th should be more than 66.
Minimum growth = [(66 - 45)/45] × 100 = 46.67% 
9. C) Number of students in class 8th in 2016 = 75 × (1 + 20/100) = 90
Number of students in class 9th in 2016 = 90 × (1 + 10/100) = 99
average number of students in classes 8th and 9th taken together in 2015 and 2016 ((75 + 90) + (90 + 99))/2 = 177
10. A) Number of students in class 8th in 2016 = 75 × (1 + 20/100) = 90
Number of students in class 9th in 2016 = 90 × (1 + 10/100) = 99
Suppose growth is T% for class 8th students in 2017.
90 × (1 + T/100) = 99
T = (99/90 - 1) × 100 = 10
Growth should be 10%.