Number Concepts and Operations

The given digits are 3, 6, 8 and 7.
Here, 3 < 6 < 7 < 8
In order to form the largest three-digit number, we have to place digits 8, 7, and 6 at the hundreds, tens, and ones place, respectively. Thus, the required largest three-digit number is 876. Hence, the correct option is (5).

The given expansion is
8 x 10000000 + 8 x1000000 + 1 x 100000 + 4 x 10000 + 2 x 100 + 1 x1 = 8 crores + 8 ten lakhs + 1 lakh + 4 ten thousands + 2 hundreds + 1 ones = 88140201
Thus, the number 88140201is equivalent to the given expansion. Hence, option (1) is correct.

The two given numbers are 9,38,278 and 62,499.
The number 9,38,278 can be rounded-off to the nearest ten thousands as 9,40,000.
<o:p>Similarly, the number 62,499 can be rounded-off to the nearest ten thousands as 60,000.
Thus, the approximated sum of the numbers 9,38,278 and 62,499 can be calculated by adding the numbers 9,40,000 and 60,000.
9,40,000 + 60,000 = 10,00,000
The correct answer is  option (5). 

The given numbers are 2627, 8612, 8126 and 3716.
When a set of numbers is arranged in descending order, the numbers are written in such a manner that the greatest number is placed at the beginning of the sequence; the second greatest number is placed after that and so on. The given numbers can be arranged in descending order as 8612 > 8126 > 3716 > 2627.
Hence, option (3) is correct. 

The given digits are 6, 4, 5, and 9.
Here, 4 < 5 < 6 < 9
We have to form a four-digit number such that digit 6 is always at the ones place.
In order to form the greatest four-digit number, we have to place digits 9, 5, and 4 at the thousands, hundreds and tens place respectively and 6 at the ones place. 
Therefore, the number so formed is 9546.
Similarly, the smallest four-digit number will have 4 at the thousands place, 5 at the hundreds place, 9 at the tens place, and 6 at the ones place. The number so formed is 4596.
Therefore, the smallest and the greatest numbers that can be formed by the digits 6, 4, 5 and 9 such that digit 6 is always at the ones place and no digit is repeated are 4596 and 9546, respectively.
Hence, the required difference is 9546 - 4596 = 4950
The correct option is (4). 

Prakash's monthly salary is Rs. 16,180.
His monthly saving = Rs. 8,870 
The numbers 16,180 and 8,870 can be rounded off to the nearest thousands as 16,000 and 9000, respectively.
Thus, Prakash's approximate monthly expenditure is 
= Rs. 16,000 - Rs. 9000
= Rs. 7,000
The correct answer is option (4).

Amount of money Ramu earns in a month = Rs. 12,400
Number of months in a year = 12
Therefore, the amount of money Ramu earns in a year can be 12,400 * 12 = Rs. 1,48,800
Thus, Ramu earns Rs. 1,48,800 in a year. Hence, option (3) is correct. 

The expression {(30 + 45) / 5} + {(18 - 3) x 20} can be solved by simplifying the brackets.
{(30 + 45) / 5} + {(18 - 3) x 20}
= {75 / 5} + {15 x 20}
= 15 + 300
= 315 
Hence, the value of the given expression is 315.
The correct answer is option (1). 

Radhika's monthly salary in May = Rs. 13,500. 

Increase in salary = Rs. 2,150

Therefore, her current monthly salary can be obtained by adding Rs. 2,150 to Rs. 13,500.

Thus, her current monthly salary is Rs. 15,650.

The correct answer is option (2). 

It is known that 1 kg = 1000 g
Therefore, 50 kg = 50 * 1000 g = 50,000 g 
8 kg = 8 * 1000 g   = 8000 g
6 kg = 6 * 1000 g = 6000 g 
9 kg = 9 * 1000 g = 9000 g
Therefore, the correct answer is option (3).

The given Roman numerals are LVI and XCIV.
LVI = L + VI
= 50 + 6  [L = 50; VI = 6]
= 56
XCIV = XC + IV
= (100 - 10) + 4  [X = 10; C = 100; IV = 4]
= 94
Therefore, LVI + XCIV = 56 + 94 
= 150
The correct answer is option (3).

Amount of honey with Priya = 9 Litres
= 9 * 1000 ml
= 9,000 ml
Amount of honey sold = 7,500 ml
Therefore, the amount of honey left with Priya can be, 9,000 - 7,500 = 1,500 ml. 
Thus, 1,500 ml of honey is left with Priya.
The correct answer is option (2).

Since 20 > 6, the difference of 20 and 6 can be represented as (20 - 6).
Accordingly, the multiplication of 39 with the difference of 20 and 6 can be represented as 39 x (20 - 6).
Thus, the required expression is 39 x (20 - 6).
The correct answer is option (4). 

Praveen's current age is 12 years. 
Three times the current age of Praveen = (3 * 12) years 
It is given that Priya's current age is four more than three times the current age of Praveen.
Thus, Priya's current age (in years) is 4 + (3 * 12).
The correct answer is option (2).

The given Roman numerals are LV and XCIII.
The first numeral can also be written as LV = L + V = 50 + 5      ..........[L = 50; V = 5] 
= 55
The second numeral can also be written as XCIII = XC + III
= (100 - 10) + 3      ................[X = 10; C = 100; III =3]
= 93
Therefore, LV x XCIII = 55 * 93
= 5115
The correct answer is option (1).