Discussion
Home ‣ Aptitude ‣ Problems on Numbers Comments
- Question
Three numbers which are co-prime to each other are such that the product of the first two is 551 and that of the last two is 1073. The sum of the three numbers is :
Options- A. 83
- B. 89
- C. 85
- D. 79
- Correct Answer
- 85
ExplanationSince the numbers are co-prime, they contain only 1 as the common factor.
Also, the given two products have the middle number in common.
So, middle number = H.C.F of 551 and 1073 = 29;
First number = 551/29 = 19
Third number = 1073/29 = 37.
Required sum = 19 + 29 + 37 = 85. - 1. The series of differences between consecutive prime numbers is represented as Cp1, Cp2, Cp3, .... Cpn , Whare Cp1 is the difference between the second and the first prime number. Find the sum of series when n = 23, given that the 23rd prime number is 83 ?
Options- A. 87
- B. 81
- C. 83
- D. 85 Discuss
- 2. Total 100 members are writing exam. In that 48 members are writing first exam, 45 members are writing second exam and 38 members are writing third exam. 5 members are writing all the three exams. How many members are writing 2 exams ?
Options- A. 26
- B. 23
- C. 27
- D. 21 Discuss
- 3. Srinivas bought 10 cycles for Rs. 1,750 each. He sold 4 cycles for Rs 8,400, 3 for Rs 1900 each . At what price should he sell the remaining cycles so as to earn an average profit of Rs 320 per cycle ?
Options- A. Rs. 1580
- B. Rs. 2200
- C. Rs. 1785
- D. Rs. 1950 Discuss
- 4. There are 5 consecutive odd numbers. If the difference between square of the average of first two odd number and the of the average last two odd numbers is 396, what is the smallest odd number?
Options- A. 29
- B. 27
- C. 31
- D. 33 Discuss
- 5. Half the people on a bus get off at each stop after the first, and no one gets on after the first stop. If only one person gets off at stop number 7, how many people got on at the first stop?
Options- A. 128
- B. 64
- C. 32
- D. 16 Discuss
- 6. What will be added to the unit digits of the number 86236 so that number will be divisible by 9 ?
Options- A. 1
- B. 2
- C. 3
- D. 0 Discuss
- 7. A number when subtracted by 1/7 th of itself gives the same value as the sum of all the angles of a triangle. What is the number?
Options- A. 420
- B. 210
- C. 70
- D. 35 Discuss
- 8. A natural number when increased by 12 equals 160 times its reciprocal. Find the number?
Options- A. 20
- B. 12
- C. 8
- D. 4 Discuss
- 9. If 50 is subtracted from two-third of a number, the result is equal to sum of 40 and one-fourth of that number. What is the number ?
Options- A. 156
- B. 179
- C. 198
- D. 216 Discuss
- 10. The difference between a two-digit number and the number obtained by interchanging the two digits is 63. Which is the smaller of the two numbers ?
Options- A. 12
- B. 15
- C. 17
- D. none of these answers can be determined Discuss
Problems on Numbers
Search Results
Correct Answer: 87
Explanation:
Cp1 = p2 - p1 ,
Cp2 = p3 - p2
..
..
..
Cp23 = p24 - p23
Sum of series = (p2-p1) + (p3-p2) + .....(p23-p22) + (p24-p23)
All terms get cancelled, except p1 = 2 and p24 = 89
So Sum = -p1 + p24
Sum of series = -2 + 89 = 87
Correct Answer: 21
Explanation:
Total number of exams written by 100 students = 48 + 45 + 38 = 131
Now let us say x members are writing only 1 exam, y members are writing only 2 exams, z members are writing only 3 exams.
Therefore, x + 2y + 3z = 131 also x + y + z = 100.
Given that z = 5. So x + 2y = 116 and x + y = 95.
Solving we get y = 21.
So 21 members are writing exactly 2 exams.
Correct Answer: Rs. 2200
Explanation:
He sold 4 cycles for Rs. 8400
[It means each cycle price is Rs. 2100]
And again he sold 3 cycles for Rs. 1900 each
If he want to gain avg profit on each cycle is Rs. 320 per cycle.
So profit for 10 cycles is @ Rs.320 is,
10 x 320 = Rs. 3200
He already got Rs. 1850 profit by selling 7 cycles.
Now, remaining amount is 3200 - 1850 = 1350
So from remaining 3 cycles we want to get Rs. 1350 profit ,
1350/3 = 450
so he must sell remaining 3 cycles at Rs. 2200 each one.
Correct Answer: 29
Explanation:
Let the five consecutive odd numbers be x-4, x-2, x, x+2, x+4
According to the question,
Difference between square of the average of first two odd number and the of the average last
two odd numbers is 396
i.e, x+3 and x-3
Hence, the smallest odd number is 33 - 4 = 29.
Correct Answer: 64
Explanation:
7th stop only one was left and in each preceding stop twice the nos... there were so 6 stops before 7th.
so
Correct Answer: 2
Explanation:
A number is divisible by 9 only if the sum of the digits of the number is divisible by 9.
Here 86236 = 8 + 6 + 2 + 3 + 6 = 25
We must add 2 to 25 to become 27 which is divisible by 9.
Correct Answer: 210
Explanation:
Let the required number be 'p'
We know, sum of angles in a triangle are 180 deg
According to given data,
p - p/7 = 180
7p - p = 180 x 7
=> 6p = 1260
=> p = 1260/6 = 210
Correct Answer: 8
Explanation:
Let the required number be 'p'.
From the given data,
p + 12 = 160 x 1/p
=> p + 12 = 160/p
=> p(p + 12) = 160
=> P^2 + 12p - 160 = 0
=> p^2 + 20p - 8p - 160 = 0
=> P(p + 20) - 8(p + 20) = 0
=> (p + 20)(p - 8) = 0
=> p = -20 or p = 8
As, given the number is a natural number, so it can't be negative.
Hence, the required number p = 8.
Correct Answer: 216
Explanation:
Let the number be x.
Then, 2/3x-50 = 1/4x +50
=> 5/12x = 90
x = (90 x 12) / 5 = 216
Correct Answer: none of these answers can be determined
Explanation:
Let the ten's digit be x and unit's digit be y.
Then, (10x + y) - (10y + x) = 63
=> 9 (x - y) = 63
=> x - y = 7.
Thus, none of the numbers can be deermined..
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.