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Download Mains Level Percentage Questions with Detailed Explanation for SBI, IBPS and RBI Grade B 2021

Directions : Read the following questions carefully and choose the right answer.
1
Arjun kapoor and Anil Kapoor appear for a test. For each correct answer is awarded 1 mark and for each wrong answer 1/2 mark is deducted. Arjun kapoor answers some questions and gets 10% of his answers wrong. He secures a score of 85% which is 6 marks more than the pass marks. Anil Kapoor also answers some questions and gets 20% of his answers wrong. He gets a score of 70% which is 3 marks less than the pass mark. No marks are awarded or deducted for the unanswered questions. What is the pass mark?
» Explain it
C
Let Arjun kapoor attempt x questions, he gets 10% of the answers wrong.
 
Arjun kapoor’s score = 0.9x – (0.1x) ×  1  = 0.85x
2
0.85x = 0.85z, where z is the total number of marks as well as total number of marks possible.
 
So, x = z ⇒ x = 100% of z
 
Similarly let Anil Kapoor attempt y questions
 
Anil kapoor’s score = 0.8y – (0.2y) ×  1  = 0.7y
2
 
0.7y = 0.7z ⇒ y = 100% of z
 
Now, 0.85z = P + 6, where P is pass mark …….. (i)
 
Also, 0.7z = P – 3 …….. (ii)
 
From (i) and (ii), we get
 
0.15z = 9 ⇒ z = 60
 
Putting the value of z in (ii), we get
 
0.7 × 60 = P – 3 ⇒ p = 42 + 3 = 45
 
Hence, option (C) is correct.
2
This year, the cost of a Tomato increased by 20% over that of the last year. Last year a Tomato costed Rs.10 and a Potato costed Rs.5. This year it costs Rs.11 more to buy 5 Potato and 3 Tomato. Find the percentage increase in the price of the Potato.
» Explain it
D
Cost of the Tomato last year = Rs.10
 
So, Cost of the Tomato this year = 10 + 20% of 10 = Rs.(10 + 2) = Rs.12
 
Cost of the Potato last year = Rs.5
 
Let the cost of Potato this year be x
 
Therefore, cost of 5 Potato and 3 Tomato this year = 5x + (3 × 12) = 5x + 36 ….. (i)
 
cost of 5 Potato and 3 Tomato last year = ((5 × 5) + (3 × 10)) = 55 …….. (ii)
 
This year the cost is Rs.11 more
 
From (i) and (ii), we get
 
5x + 36 = 55 + 11 ⇒ 5x = (66 – 36) ⇒ x = 6
 
Increase in the cost of Potato = (6 – 5) = Rs. 1
 
Percentage increase =  1  × 100% = 20%
5

Hence, option (D) is correct.
3
Fresh sugarcane contains 84% water and dried sugarcane contains 28% water. How many kilograms of dried sugarcane can be obtained from 90 kg of fresh sugarcane?
» Explain it
A
The quantity of pulp (the part that is not water) in 90 kg of fresh sugarcane

16  × 90 kg.
100

This is also the quantity of pulp in the dried sugarcane formed.

Dried sugarcane have 72% pulp

16  × 90 =  72
100 100

(Quantity of dried sugarcane formed) =  72  × X (Say)
100

⇒ X = 20

Hence, option (A) is correct.
4
In Kolkata consisting of three localities Salt Lake, South Kolkata and Rajarhat the population of the three localities Salt Lake, South Kolkata and Rajarhat are in the ratio 9 : 8 : 3. In Salt Lake, 80% of the people are literate, in South Kolkata, 30% of the people are illiterate. If 90% people in Rajarhat are literate. Find the percentage literacy in these three localities in Kolkata.
» Explain it
A
Let the population of Salt Lake = 9x, 
 
The population of South Kolkata = 8x, and 
 
The population of Rajarhat = 3x
 
The total population of these three localities = 9x + 8x + 3x = 20x
 
The number of literate in Salt Lake = 80% of 9x = 7.2x
 
The number of literate in South Kolkata = 70% of 8x = 5.6 x
 
The number of literate in Rajarhat = 90% of 3x = 2.7x
 
The total number of literate in these three localities = 7.2x + 5.6x + 2.7x = 15.5x

Hence. Required percentage =  15.5 x  × 100 = 77.5%
20x

Therefore, option (A) is correct.
5
ln an election of 3 candidates , Narendra Modi, Rahul Gandhi and Arvind Kejriwal. Narendra Modi gets 40% more votes than Rahul Gandhi . Narendra Modi also beats Arvind Kejriwal by 54000 votes. If it is known that Rahul Gandhi gets 10% more votes than Arvind Kejriwal, find the number of voters on the voting list (given 90% of the voters on the voting list voted and no votes were illegal)
» Explain it
A
Let Narendra Modi is denoted by M, Rahul Gandhi is denoted by R and Arvind Kejriwal is denoted by A. 

Now let R gets vote = x    ......(I) 

M = 1.4x       .......(II) 

M –  A = 54000     ........(III) 

R = 1.1A        .........(IV) 

From equation (II) and (IV) we get,

M = 1. 4 × 1.1A = 1.54 A        ......(V)

From equation (III) and (V) we get.,

0.54A = 54000

A = 100000

M = 1.54 × 10000 = 154000

R = 1.1 × 100000 = 110000

Hence total votes pole in election = (154000 + 110000 + 100000) = 364000

From question 90% of total votes pole on voting list.

Hence vote in voting list =  364000 × 100  = 404444
90

Therefore, option (A) is correct.