Tag: maths

Questions Related to maths

Select the correct option.
The HCF and the LCM of $12, 21, 15$ respectively are

maths be my multiple, i'll be your factor co-prime numbers lcm lowest common multiple (l.c.m.)

  1. $3, 140$

  2. $12, 420$

  3. $3, 420$

  4. $420, 3$

Show answer
Correct Option: A
Explanation:

Numbers $= 12, 15, 21$


$12 =  2 \times 2 \times 3$


$15 = 3 \times 5$

$21 = 3 \times 7$

HCF = Product of smallest power of each common prime factor $= 3' = 3$
LCM = Product of greatest power of each prime factor 

$2^2 \times 3 \times 5 \times 7 = 4 \times 3 \times 5 \times 7 = 420$

$(C) \,\, 3, 420$

The greatest number which when subtracted from 5834, gives a number exactly divisible by each of 20, 28, 32 and 35 is

maths be my multiple, i'll be your factor co-prime numbers lcm lowest common multiple (l.c.m.)

  1. 1120

  2. 4714

  3. 5200

  4. 5600

Show answer
Correct Option: B
Explanation:

 Number which is exactly divisible by 20, 28, 32 and 35 should be the common multiple of all these.
$20 = 2^2 \times 5$
$28 = 2^2 \times 7 \Rightarrow 32 = 2^5$
35.=5 $\times $ 7
LCM = $2^5 \times 5 \times 7 = 1120$
Hence the greatest number that should be subtracted
=5834-1120 = 4714

By selling 32 clips for a rupee, a man loses 40%. How many a rupee must he sell to gain 20%?

maths comparing quantities using proportion overhead expenses introduction to total cost price of the article profit and loss with overhead expenses

  1. 64

  2. 30

  3. 24

  4. 16

Show answer
Correct Option: D
Explanation:

b'S.P. of 1 clip $\displaystyle=\frac{1}{32}$ of a rupee

$\implies$ 60% of CP $\displaystyle=\frac{1}{32}$ of a rupee

$\therefore$ 120% of CP $\displaystyle=\frac{1}{32}\times\frac{120}{60}$ i.e. $\displaystyle\frac{1}{16}$ of a rupee

$\implies$ he should sell 16 clips for a rupee.'

Reshma sells an article to Rekha at $37.5\%$ profit, Rekha sells it to Madhu at $9\dfrac{1}{11}\%$ profit. Again Madhu sells it to Mitu at $25\%$ loss. If Mitu pays $Rs\ 342$ for the article, then what is the cost price of the article to Reshma?

maths comparing quantities using proportion overhead expenses introduction to total cost price of the article profit and loss with overhead expenses

  1. $Rs\ 304$

  2. $Rs\ 266.50$

  3. $Rs\ 380$

  4. $Rs\ 384.75$

Show answer
Correct Option: A

By selling a watch for Rs 480, a man gains 25%. How much per cent would he gain by selling it for Rs 432?

maths comparing quantities using proportion overhead expenses introduction to total cost price of the article profit and loss with overhead expenses

  1. $15\%$

  2. $\displaystyle6\frac{1}{4}\%$

  3. $\displaystyle12\frac{1}{2}\%$

  4. $25\%$

Show answer
Correct Option: C

Choose the correct answer from the alternatives given :
Mr. Ram runs a clothing store. His overhead expenses are 32% and his profits are 12% of his sale. At what price should he sell a raincoat which costs him Rs. 10.50 ?

maths comparing quantities using proportion overhead expenses introduction to total cost price of the article profit and loss with overhead expenses

  1. Rs. 13

  2. Rs. 15.52

  3. Rs. 12

  4. Rs. 19

Show answer
Correct Option: B
Explanation:
Cost price of umbrella $=Rs.10.50$
    overhead expenses $=32$% $=0.32$
            Required profit $=12$% $=0.12$
So, Selling price of umbrella $=Rs.10.50\times 1.32\times 1.12$
                                                $=Rs.15.52$
So, selling price $=Rs.10.50\times 1.32\times 1.12$
                           $=Rs.15.52$.

What is the value of mean for the following data:

Marks No. of Student
$5-14$ $10$
$15-24$ $18$
$25-34$ $32$
$35-44$ $26$
$45-54$ $14$
$55-64$ $10$
mean and median mean maths assumed mean method assumed mean method of finding mean measure of central tendency

  1. $30$

  2. $29$

  3. $33.68$

  4. $34.21$

Show answer
Correct Option: C

Mr. R purchases $20\ kgs$. of Wheat, $10\ kgs.$ of rice and $2\ kgs.$ of ghee every month. If the price of wheat is $Rs. 10$ per kg., price of rice is $Rs. 14$ per kg. and price of ghee is $Rs. 120$ per kg. Find the average price per kg. per month. Arithmetic mean $=$?

mean and median mean maths assumed mean method assumed mean method of finding mean measure of central tendency

  1. $48$

  2. $18.125$

  3. $48.125$

  4. $18$

Show answer
Correct Option: B

If there are two groups containing $30$ and $20$ observations and having $50$ and $60$ as arithmetic means, then the combined arithmetic mean is ________.

mean and median mean maths assumed mean method assumed mean method of finding mean measure of central tendency

  1. $55$

  2. $56$

  3. $54$

  4. $52$

Show answer
Correct Option: C

What is the value of mean for the following data.

Class interval Frequency
$350-369$ $15$
$370-389$ $27$
$390-409$ $31$
$410-429$ $19$
$430-449$ $13$
$450-469$ $6$
mean and median mean maths assumed mean method assumed mean method of finding mean measure of central tendency

  1. $400$

  2. $400.58$

  3. $394$

  4. $394.50$

Show answer
Correct Option: B
Explanation:
Class Intervals Mid-values(x) Frequency(f) fx
$350-369$ $359.5$ $15$ $5,392.5$
$370.389$ $379.5$ $27$ $10,246.5$
$390-409$ $399.5$ $31$ $12,384.5$
$410-429$ $419.5$ $19$ $7,970.5$
$430-449$ $439.5$ $13$ $5,713.5$
$450-469$ $459.5$ $6$ $2,757$
$\displaystyle\sum f=111$ $\displaystyle\sum fx=44,464.5$

Arithmetic mean $=44,464.5/111=400.58$.