Test-Series - numerical

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
29
30
31
32
33
34
35
36
37
38
39
40

Test Number 6/39

Q: What is the place value of 6 in 64?
A. 60
B. 10
C. 64
D. 6
Solution: We know that, ● Each digit has a fixed position called its place. ● Each digit has a value depending on its place called the place value of the digit. ● The face value of a digit for any place in the given number is the value of the digit itself ● Place value of a digit = (face value of the digit) × (value of the place).   Hence, the place value of 6 in 64 = 6 x 10 = 60.
The correct answer is: B) 60
Q: 8 litres are drawn from a cask full of wine and is then filled with water. This operation is performed three more times. The ratio of the quantity of wine now left in cask to that of the water is 16 : 65. How much wine the cask hold originally?
A. 42 litres
B. 24 litres
C. 18 litres
D. 32 litres
Solution: Let the quantity of the wine in the cask originally be x litres  Then, quantity of wine left in cask after 4 operations =x1-8x4litres   ∴x1-8x4x = 1681      ⇒1-8x4=234    ⇒x=24
The correct answer is: B) 24 litres
Q: L.C.M of two prime numbers x and y (x>y) is 161. The value of 3y-x is :
A. -2
B. -1
C. 2
D. 1
Solution: H. C. F of two prime numbers is 1.  Product of numbers = 1 x 161 = 161.  Let the numbers be a and b . Then , ab= 161.  Now, co-primes with  product 161 are (1, 161) and (7, 23).  Since x and y are prime numbers and x >y , we have x=23 and y=7.  Therefore,  3y-x = (3 x 7)-23 = -2
The correct answer is: A) -2
Q: How much time will take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest  ?
A. 3.5 years
B. 2.5 years
C. 2 years
D. 4 years
Solution: Time = (100 x 81) / (450 x 4.5) = 4 years.
The correct answer is: A) 4 years
Q: A number is decreased by 10% and then increased by 10%.  The number so obtained is 10 less than the original number. What was the oiginal number ?
A. 2000
B. 3000
C. 1000
D. 4000
Solution: Let the original number be x.   Final number obtained = 110% of (90% of x) =(110/100 * 90/100 * x) = (99/100)x.    x-(99/100)x=10 => x =1000
The correct answer is: A) 1000
Q: Insert the missing number. 3, 7, 6, 5, 9, 3, 12, 1, 15, (....)
A. 18
B. -1
C. 13
D. 3
Solution: There are two series, beginning respectively with 3 and 7. In one 3 is added and in another 2 is subtracted. The next number is 1 - 2 = -1.
The correct answer is: C) -1

Q: What least number must be subtracted from 13601, so that the remainder is divisible by 87 ?
A. 29
B. 37
C. 31
D. 23
Solution: 87)13601(156       87        -----       490       435        -----        551        522         -----         29         ----- Required number is 29.
The correct answer is: C) 29

You Have Score    /7