Tag: square and square root

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Questions Related to square and square root

Multiple choice maths square and square root scientific notation use of exponents power of 10

The digit in the ten's place of a two-digit number is three times that in the one's places if the digits are reversed the new number will be 36 less than the original number Find the number 

  1. 64

  2. 52

  3. 62

  4. 42
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the digits be $ x $ and $ y $
Given, "The digit in the ten's place of a two-digit number is three times that in the one's places "
$ => x = 3y $ 

Now, when the digits are reversed, the number will be $ 10y + x $
Also,  if the digits are reversed the new number will be $ 36 $ less than the original number. $ => 10y + x = (10x + y) - 36 $
$ => 9x -9y = 36 $

Putting $ x = 3y $ in this,
$ 9(3y) -9y = 36 $
$ => 27y - 9y = 36 $
$ 18y = 36 => y = 2 $

So, $ x = 3y = 6 $
Hence, the number is $ 62 $

Multiple choice maths square and square root scientific notation use of exponents power of 10

Which of the following options is INCORRECT?

  1. The number $48693$ rounded off to nearest hundred is $48700$

  2. LXXV is greater than LXXIV
  3. One million is equal to $10$ crore
  4. Place value of a digit $=$(face value of the digit)$\times$ (Value of the place)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option A: For rounding to the nearest hundred, If tens digit is 0,1,2,3,4

, then round down to the previous hundred and If tens digit is 5,6,7,8,9, then round up to the next hundred.
Following the above rule, as 6 is present in the hundredth place, we will round up it to $700$.

Hence $48693$ $\rightarrow$ $48700$.

Option B: LXXV $\rightarrow$ $75$
                 LXXIV $\rightarrow$ $74$
So, LXXV $>$ LXXIV

Option C: 1 million $\rightarrow$ 10,00,000 $\rightarrow$ 10lakh

Option D: Face value is the value of the digit itself.
Value of place if the position of the digit in the number
Hence, Place value $\rightarrow$ face value $\times$ Value of place

Hence Option C is incorrect.





Multiple choice maths square and square root scientific notation use of exponents power of 10

In scientific notation, $670,000,000 + 700,000,000 =$?

  1. $1.37 \times {10}^{-9}$
  2. $1.37 \times {10}^{7}$
  3. $1.37 \times {10}^{8}$
  4. $1.37 \times {10}^{9}$
  5. $137 \times {10}^{15}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$670,000,000+700,000,000=1,370,000,000$

$\therefore 1,370,000,000=1.37\times 10^9$
Ans-Option $D$.

Multiple choice maths square and square root scientific notation use of exponents power of 10

Choose the correct answer from the alternatives given.
Select the correct combination of mathematical signs to replace * signs and to balance the following equation.
7*5*5*4* 10

  1. + $\div$ - =
  2. $\times $ - = $\times $
  3. $\times $ + = $\times$
  4. + $\times \div $ =
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Given,

$7**5*4* 10$

Now, we have

$7 \times5 + 5 = 4 \times 10$

$35+5=4 \times 10$

$40 =40$
Multiple choice maths square and square root scientific notation use of exponents power of 10

If $x$ and $y$ are any two positive real numbers, then $x > y$ implies

  1. $- x > - y$
  2. $- x < - y$
  3. $\frac{1}{x} > \frac{1}{y}$
  4. $-\frac{1}{x} > \frac{1}{y}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$ Given\quad that\quad x\quad and\quad y\quad are\quad positive\quad number\quad and\quad x>y.\ We\quad may\quad calculate\ (a)\quad on\quad the\quad positive\quad side\quad of\quad number\quad line\quad x\quad will\quad be\ \quad \quad to\quad the\quad right\quad of\quad y\quad and\quad \ (b)\quad on\quad the\quad negative\quad side\quad of\quad the\quad number\quad line\quad x\quad will\ \quad \quad be\quad to\quad the\quad left\quad of\quad y.\ Statement\quad A\longrightarrow -x>-y\quad i.e\quad -x\quad to\quad the\quad right\quad side\quad of\quad -y\ which\quad is\quad not\quad complying\quad with\quad (b).\quad So\quad it\quad is\quad not\quad true.\ Statement\quad B\longrightarrow -x<-y\quad i.e\quad -x\quad lies\quad to\quad the\quad left\quad of\quad -y.\ This\quad complies\quad with\quad (b).\quad So\quad the\quad statement\quad is\quad true.\ Statement\quad C\longrightarrow \frac { 1 }{ x } >\frac { 1 }{ y } .\quad Here\quad the\quad numerators\quad of\quad the\ two\quad fractions\quad are\quad equal.\quad But\quad the\quad denominator\quad of\quad \frac { 1 }{ x } \ is\quad greater\quad than\quad that\quad of\quad \frac { 1 }{ y } .\ So\quad this\quad statement\quad is\quad not\quad true.\ Statement\quad D\longrightarrow -\frac { 1 }{ x } >\frac { 1 }{ y } ,\ -\frac { 1 }{ x } is\quad a\quad negative\quad number\quad so\quad it\quad will\quad always\quad be\quad smaller\ than\quad a\quad positive\quad number.\ \therefore \quad -\frac { 1 }{ x } \ngtr \frac { 1 }{ y } .\quad So\quad this\quad statement\quad is\quad not\quad true.\ Answer-\quad Statement\quad B\quad is\quad correct.\  $