Quant Quiz on Percentage
1. Two students appeared at an examination. One of them secured 9 marks more than the other and his marks was 56% of the sum of their marks. The marks obtained by them are
(a) 36, 46
(b) 42, 33
(c) 24, 64
(d) None of these
2. A fruit seller had some apples. He sells 40% apples and still has 420 apples. Originally, he had:
(a) 600 Apples
(b) 700 Apples
(c) 500 Apples
(d) None of these
3. What percentage of numbers from 1 to 70 has 1 or 9 in the unit's digit?
(a) 20
(b) 22
(c) 21
(d) None of these
4. If A = x% of y and B = y% of x, then which of the following is true?
(a) A is smaller than B.
(b) A is greater than B
(c) Relationship between A and B cannot be determined.
(d) None of these
5. In a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is 2/3 of the number of students of 8 years of age which is 48. What is the total number of students in the school?
(a)50
(b)100
(c)80
(d)72
6. A student multiplied a number by 3/5 instead of 5/3. What is the percentage error in the calculation?
(a)34%
(b)44%
(c)54%
(d)64%
7. In an election between two candidates, one got 55% of the total valid votes, 20% of the votes were invalid. If the total number of votes was 7500, the number of valid votes that the other candidate got, was:
(a) 3000
(b)2700
(c)2900
(d) 3500
8. Three candidates contested an election and received 1136, 7636 and 11628 votes respectively. What percentage of the total votes did the winning candidate get?
(a) 57%
(b)60%
(c)65%
(d) 90%
9. Helen went to the stationers and bought things worth Euro 25, out of which 30 paise went on sales tax on taxable purchases. If the tax rate was 6%, then what was the cost of the tax free items?
(a) Euro 15
(b) Euro 15.7
(c) Euro 19.7
(d) Euro 20
10. The population of a town increased from 1,75,000 to 2,62,500 in a decade. The average percent increase of population per year is:
(a) 4.37%
(b) 5%
(c) 6%
(d) 8.75%
Answer With Explanation
1. (b)
Explanation: Let their marks be (x + 9) and x.
Then, x + 9 = 56/100(x + 9 + x)
25(x + 9) = 14(2x + 9)
3x = 99
x = 33
So, their marks are 42 and 33.
2. (b)
Explanation: Suppose originally he had x apples.
Then, (100 - 40)% of x = 420.
60/100 x x = 420
x = (420 x 100)/60 = 700
3. (a)
Explanation: Clearly, the numbers which have 1 or 9 in the unit's digit, have squares that end in the digit 1.
Such numbers from 1 to 70 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.
Number of such number =14
Required percentage = (14/70 x 100)% = 20%.
4. (d)
Explanation: x% of y = (x/100 x y) = (y/100 x x) = y% of x
A = B.
5. (b)
Explanation: Let the number of students be x.
Then, Number of students above 8 years of age = (100 - 20)% of x = 80% of x.
80% of x = 48 + 2/3 of 48
80/100x = 80
x = 100.
6. (d)
7. (b)
Explanation: Number of valid votes = 80% of 7500 = 6000.
Valid votes polled by other candidate = 45% of 6000
= (45/100 x 6000) = 2700.
8. (a)
Explanation: Total number of votes polled = (1136 + 7636 + 11628) = 20400.
Required percentage = (11628/20400 x 100)% = 57%.
9. (c)
Explanation: Let the amount taxable purchases be Euro x.
Then, 6% of x = 30/100
x = (30/100 x 100/6) = 5.
Cost of tax free items = Euro [25 - (5 + 0.30)] = Euro 19.70
10. (b)
Explanation: Increase in 10 years = (262500 - 175000) = 87500.
Increase% = (87500/175000 x 100)% = 50%.
Required average = (50/10)% = 5%.