Tag: calculations and mental strategies 1

Quizzes (1) Questions (116)

Questions Related to calculations and mental strategies 1

Multiple choice maths calculations and mental strategies 1 equations from statements forming equations from statements writing mathematical statements

Equation for the statement: 'thrice the length (L) of a room is 340 metres'

  1. $3L = 43$
  2. $3L = 340$
  3. $3 + L= 34$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\Rightarrow$  The length of room is $L.$

$\Rightarrow$  So, thrice the length means $3L.$

The equation for thrice the length of the room is $340 \ meters$

$\Rightarrow$  $3L=340\ meters.$

Multiple choice maths calculations and mental strategies 1 equations from statements forming equations from statements writing mathematical statements

The equation for the statement:"half a number added to 10 is 15".

  1. $\dfrac{X}{2}\,+ 10\,+ 5$
  2. $\dfrac{X}{2}\,+ 10\,= 5$
  3. $\dfrac{X}{2}\,+ 15\,= 10$
  4. $\dfrac{X}{2}\,= -10\,+ 15$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the number be $X.$

Half of the number is $\dfrac{X}{2}$
Half a number added to $10$ is $\dfrac{X}{2}+10$
So, according to the question,
$\Rightarrow$  $\dfrac{X}{2}+10=15$

$\Rightarrow$  $\dfrac{X}{2}=-10+15$

Multiple choice maths calculations and mental strategies 1 equations from statements forming equations from statements writing mathematical statements

In three coloured boxes - Red, Green and Blue, $108$ balls are placed. There are twice as many balls in the green and red boxes combined as there are in the blue box and twice as many in the blue box as there are in the red box. How many balls are there in the green box?

  1. $18$
  2. $36$
  3. $45$

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let R, G, B be the number of balls. We have R+G+B=108, G+R=2B, and B=2R. Substituting B=2R into the second equation gives G+R=4R, so G=3R. Substituting into the sum: R+3R+2R=108, so 6R=108, R=18. Then G=3(18)=54. Since 54 is not an option, the correct answer is None of these.

Multiple choice maths calculations and mental strategies 1 equations from statements forming equations from statements writing mathematical statements

The equation for the statement; 'Half of a number added to $10$ is $15$' is __________.

  1. $\dfrac {x}{2} = 10 + 5$
  2. $\dfrac {x}{2} + 10 = 15$
  3. $\dfrac {x}{2} = 15 + 10$
  4. $\dfrac {x}{2} = 10 + 15$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let, the number be $x$
Half of a number $=$ $\dfrac{x}{2}$
Therefore, the required equation is $\dfrac{x}{2}$ $+10 = 15$.

Multiple choice maths calculations and mental strategies 1 equations from statements forming equations from statements writing mathematical statements

Kapil bought some packets of pens. He bought one packet containing $5$ pens and $n$ packets containing $2$ pens each. Which of the following expressions could be used to find the total number of pens that Kapil bought ? 

  1. $7n$
  2. $10n$
  3. $5 + 2n$
  4. $2 + 5n$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Number of packets bought $= 1 + n$

Given that, 
Single packet has $5$ pens and $n$ packets have $2$ pens each
$\therefore$ Total number of pens in $n$ packets $= 2n$

$\therefore$ Total number of pens bought by Kapil $= 2n + 5$