Tag: operations

Quizzes (1) Questions (91)

Questions Related to operations

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

Savita has Rs. 27 in the form of fifty paise and twenty-five paise coins. She has twice as many twenty-five paise coins as she has 50 paise coins. How many coins of each kind does she have?

  1. 27, 54

  2. 30, 60

  3. 25, 50

  4. 40, 80
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the number of 50 paise coins =x
So the number of 25 paise coins=2x
Amount with 50 paise coines=0.5x
Amount with 25 paise coines=0.5x
According to question 
0.5x+0.5x=27
Or x=27
So the number of 50 paise coins=x=27
Or the number of 25 paise coines=2x=54 

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

$1+5+9+\cdots\cdots+(4n-3)$ is equal to

  1. $n(4n-3)$
  2. $(2n-1)$
  3. $n(2n-1)$
  4. $(4n-3)^2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the given Arithmetic Progression,
First term $ = a  = 1 $
Common difference $ = 5 - 1 = 4 $

Let $ 4n - 3 $ be the $  k $ th term.

Then $ {x} _{n} = a + (n-1)d $
$ => 4n- 3 = 1 + (k-1)4 $
$ => 4n -1 = 1 +4k-4 $
$ => k = n $

So,  $ 4n - 3 $ is the $ n $ th term.

Now, Sum to 'n' terms of an AP $ = \frac {n}{2} (2a+(n-1)d) = \frac {n}{2} (2+(n-1)4) = \frac {n}{2} (4n-2) =n(2n-1) $

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

The distance between (-4, -5) and (-4, -10) is________units

  1. 15

  2. 10

  3. 5

  4. 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Distance between two points $ ({x} _{1}, {y} _{1}) $ and $ ({x} _{2}, {y} _{2}) $ is $ \sqrt {{({x} _{2}-{x} _{1})}^{2} + {{(y} _{2}-{y} _{1})}^{2} } $

So, distance between $ (-4,-5) ; (-4,-10) $ is $ \sqrt {{(-4+4)}^{2} + {(-10+5)}^{2} } = 5 $

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

$\left (1 - \dfrac {1}{2}\right ) + \left (\dfrac {3}{4} - \dfrac {1}{4}\right )=$

  1. $0$
  2. $1$
  3. $\dfrac {1}{2}$
  4. $\dfrac {3}{4}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$\left ( 1-\dfrac{1}{2} \right )+\left ( \dfrac{3}{4}-\dfrac{1}{4} \right )$
$=\left ( \dfrac{2-1}{2} \right )+\left ( \dfrac{3-1}{4} \right )$
$=\dfrac{1}{2}+\dfrac{2}{4}= \dfrac{1}{2}+\dfrac{1}{2}= 1$
Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

Grace has 16 jellybeans in her pocket. She has 8 red ones, 4 green ones, and 4 blue ones. What is the minimum number of jellybeans she must take out of her pocket to ensure that she has one of each color?

  1. 4

  2. 8

  3. 12

  4. 13

  5. 16
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Grace has $8$ red , $4$ green , $4$ blue jellybeans
  • In order to have one of each color , she should take out $7$ red, $3$ green , $3$ blue jellybeans
  • So she has to take out $7+3+3=13$ jellybeans