Arithmetic Aptitude 4

Question 1

Raghav has got a bag of numbers from 1 to 500, however he want to remove the numbers those are multiple of 9. How many total numbers will be removed?

Cross

44

Tick

55

Cross

50

Cross

52



Question 1-Explanation: 
The required numbers are 9, 18, 27, 36, 45……450, 459, 468, 477, 486, 495

This is an A.P. with a = 9 and d = 9

Let it has n terms.

Then Tn = 495 = 9 + (n-1) x9

∴ 495 = 9 + 9n - 9

∴ 9n = 495

∴ n = 55
Question 2
How many terms are there in 3,9,27,81........531441?
Cross
25
Tick
12
Cross
13
Cross
14


Question 2-Explanation: 
3, 9, 27, 81..............531441 form a G.P. 
with a = 3 and r = 9/3 = 3
Let the number of terms be n
According to the formula, Nth term of the G.P is represented as Tn = a x rn-1
Then 3 x 3n-1 = 531441
∴ 3n = 312
∴ n = 12
Question 3
7 + 72 + 73...........76 =?
Cross
140136
Cross
142156
Cross
133256
Tick
137256


Question 3-Explanation: 
Given series is a G. P. with a = 7, r = 7 and n = 6

∴ Sn = a(rn-1) / (r-1)

∴ Sn = 7(76-1) / 6

  Sn = = 137256
Question 4
Two numbers are in the ratio of 2:9. If their H. C. F. is 19, numbers are:
Cross
6, 27
Cross
8, 36
Tick
38, 171
Cross
20, 90


Question 4-Explanation: 
Let the numbers be 2X and 9X
Then their H.C.F. is X, so X = 19
∴ Numbers are (2x19 and 9x19) i.e. 38 and 171
Question 5
Subhash has 90 currency notes, some of which are Rs. 1000 denomination and rest of Rs. 500 denomination. The total amount is Rs 71,000. How many notes he has in denomination of Rs. 500?
Cross
30
Cross
32
Cross
34
Tick
38


Question 5-Explanation: 
Let the no. of Rs. 500 note be X
Then the no. of Rs. 1000 note = 90 – X
∴ 500X + 1000(90 – X) = 71000
∴ 500X + 90000 – 1000X = 71000
∴ 500X = 19000
∴ X = 38
Question 6

If the average of four consecutive odd numbers is 16, find the smallest of these numbers?

Cross

5

Cross

7

Tick

13

Cross

11



Question 6-Explanation: 
Let the numbers be x, x+2, x+4 and x+6
Then (x + x + 2 + x + 4 + x + 6)/4  = 16
∴ 4x + 12 = 64
∴ x = 13
Question 7
If the sum of two numbers is 13 and the sum of their square is 85. Find the numbers?
Tick
6 & 7
Cross
5 & 8
Cross
4 & 9
Cross
3 & 10


Question 7-Explanation: 
Let the numbers be x and 13-x Then x2 + (13 – x)2 = 85 ∴ x2 + 169 + x2 – 26x = 85 ∴ 2 x2 – 26x + 84 = 0 ∴ x2 – 13x + 42 = 0 ∴ (x-6)(x-7)=0 Hence numbers are 6 & 7
There are 7 questions to complete.

  • Last Updated : 16 May, 2019

Share your thoughts in the comments
Similar Reads