Question
The sum of two numbers is 50 and their difference is 30. Find the numbers.
10,40
10,50
20,30
5,45
Solution
Correct
option
is 10,40
Let the numbers be x and y. Now, as per the given situation,
x + y = 50(i)
and x - y = 30(ii)
We can write, x = 50-y, from eq.(i),
Therefore, putting the value of x in eq(ii), we get,
50 - y - y = 30
50 -2y = 30
2y = 50- 30= 20
y = 20/2 = 10
and x = 50 - y = 50-10 =40
Therefore, the two numbers are 40 and 10.
Question
If the given number 925x85 is divisible by 11, I then the smallest value of x is: 2.
1
2
3
4
Solution
Correct
option
is 4
11 से विभाज्यता के लिए,
$\dfrac{(5+x+2)\sim (8+5+9)}{11}$
$\dfrac{(7+x)\sim 22}{11} = \dfrac{15-x}{11}$
$x = 4$
Question
If the 6-digit numbers x35624 and 1257y4 are- divisible by 11 and 72, respectively, then what is the value of (5x-2y)?
13
12
10
14
Solution
Correct
option
is 14
$\because $x35624 is divisible by 11. .
$\dfrac{(7+x)\sim13}{11} = \dfrac{x-6}{11}$
$\because x = 6$
1257y4 is divisible by 72.
Hence it will also be divisible by 9. .
y=8
5x - 2y= 30 - 16= 14
Question
The digit in the unit place of the product is $81\times 82 \times 83\times84 .. ..89 $
0
1
2
3
Solution
Correct
option
is 0
The digit in units place = units digit in the product $1\times 2 \times 3 .... 9 = 0$
Question
What is the unit digit $3 \times 38 \times 537 \times 1256$
1
8
3
5
Solution
Correct
option
is 8
Answer: (a)
Units digit in $3 \times 38 \times 537 \times 1256$
= Units digit in $ 3\times 8 \times 7\times 6$
= $ 4\times 2 = 8$