Practice questions here, for every subject and every exam. Unlimited questions for unlimited attempts, given with answers and explanations.
The cost price of an article is $\frac{7}{6}$ times the selling price. What is the loss/gain percentage (correct up to two decimal places)?
Let the selling price be $x$ Rs.
Cost price $=\frac{7}{6} \times(\mathrm{x})=\frac{7 x}{6}$
We know that:
Loss percentage $=\frac{(\text { Cost price }-\text { Selling price })}{\text { Cost price }} \times 100$
Therefore, the loss percentage $=\frac{\left(\frac{7 x}{6}-x\right)}{\left(\frac{7 x}{6}\right)} \times 100=\frac{\left(\frac{7 x-6 x}{6}\right)}{\left(\frac{7 x}{6}\right)} \times 100=\left(\frac{x}{6}\right) \times\left(\frac{6}{7 x}\right) \times 100=14.29 \%$
MATHS MIRROR SOLUTION
Let CP $=\frac{7}{6}$SP
$\frac{CP}{SP}=\frac{7}{6}$
Required loss percentage $=\frac{7-6}{7}\times100=\frac{1}{7}\times100=14.29 \%$
6 copies of a book can be bought for a certain sum payable at the end of a year, and 7 copies of the same book can be bought for the same sum in cash money. What is the rate per annum of simple interest (correct to one decimal place)?
Let the cost price of one copy of a book be x Rs.
Cost price of 6 copies of a book = 6x
Cost price of 7 copies of a book = 7x
Simple interest = 7x – 6x = x
We know that:
Simple interest $=\frac{P \times R \times T}{100}$
$
\begin{aligned}
&\Rightarrow \mathrm{x}=\frac{(6 x) \times R \times 1}{100} \\
&\Rightarrow \mathrm{R}=\frac{100 x}{6 x} \\
&\Rightarrow \mathrm{R}=16.7 \%
\end{aligned}
$
Therefore, the rate per annum of simple interest is $16.7 \%$
Direction: Study the graph and answer the question given below.
The given graph represents the number of workers getting daily wages (in₹).
Total number of workers = 200
What is the difference between the percentage of workers whose daily wages are less than 500 and the percentage of workers whose daily wages are ₹600 and above?
The percentage of workers whose daily wages are less than 500 == = 22.5%
The percentage of workers whose daily wages are ₹600 and above == = 50%
Therefore, the required difference between the percentage of workers whose daily wages are less than 500 and the percentage of workers whose daily wages are ₹600 and above = 50% - 22.5 = 27.5%
The income of a company increases by 25% per year. If its income is ₹31,25,000 in the year 2017, what was the income in 2015?
Let the income of company in 2015 be x Rs.
According to question,
(x) ×× = 3125000
(x) ×× = 3125000
$x =\frac{3125000 \times 4 \times 4}{5 \times 5}$
x = Rs. 20,00,000
Therefore, the income of company in 2015 was Rs. 20,00,000
The total number of students in class A and B is 92. The number of students in A is 30% more than that in B. The average weight (in kg) of students in B is 50% more than that of students in A. If the average weight of all the students in A and B is 56 kg, then what is the average weight (in kg) of students in B?
Total number of students in class A and B = 92
The number of students in A is 30% more than that in B.
⇒
Now,
⇒
⇒
⇒
Hence, A = 92 – B = 92 – 40 = 52
Average weight of all the students in A and B is 56 kg
Sum of weight of all the students in A and B =
Let average weight (in kg) of students in A = x kg
Let average weight (in kg) of students in B = y kg
The average weight (in kg) of students in B is 50% more than that of students in A.
Now,
⇒
⇒
⇒
Now,
Hence, average weight (in kg) of students in B = 69 kg
Ramesh invested $30 \%$ more than Suresh, Suresh invested $40 \%$ less than Arun, who invested Rs. 8,000 . The total amount invested by all of them together is:
Given:
Amount invested by Arun = 8000 Rs.
Amount invested by Suresh = 8000 × = 8000 × = 4800 Rs.
Amount invested by Ramesh = 4800 × = 48 × 130 = 6240 Rs.
Therefore, total amount invested by all of them = 8000 + 4800 + 6240 = 19040 Rs.
Let the radius of cylinder = r and height of the cylinder = h
We know that:
Volume of a cylinder =
Volume of a new cylinder =
=
=
Therefore, required percentage =
=
=
= 42.4 %
Hence, option D is correct.
A reduction of $15 \%$ in the price of sugar enables Aruna Rai to buy $6 \mathrm{~kg}$ more for Rs. 272 . The reduced price of sugar per kg is:
Let the price of sugar $=x$ per $\mathrm{kg}$
According to question,
$\Rightarrow \frac{272}{\left(x \times \frac{85}{100}\right)}-\frac{272}{x}=6$
$\Rightarrow \frac{272 \times 20}{17 x}-\frac{272}{x}=6$
$\Rightarrow \frac{320}{x}-\frac{272}{x}=6$
$\Rightarrow \frac{320-272}{x}=6$
$\Rightarrow x=\frac{48}{6}$
$\Rightarrow x=8$
Therefore, reduced price of sugar $=8 \times \frac{85}{100}=6.80$ Rs.
$A$ is $120 \%$ of $B$ and $B$ is $65 \%$ of $C$. If the sum of $A, B$ and $C$ is $121 \frac{1}{2}$, then the value of $2 C-4 B+A$ is:
The value of $B=C \times \frac{65}{100}=\frac{65 C}{100}$
The value of $A=B \times \frac{120}{100}=\frac{65 C}{100} \times \frac{120}{100}=\frac{78 C}{100}$
According to question,
$
\Rightarrow A+B+C=121 \frac{1}{2}
$
$
\Rightarrow \frac{78 C}{100}+\frac{65 C}{100}+C=\frac{243}{2}
$
$\Rightarrow \frac{78 C+65 C+100 C}{100}=\frac{243}{2}$
$\Rightarrow \frac{243 C}{100}=\frac{243}{2}$
$\Rightarrow C=50$
$A=\frac{78 C}{100}=\frac{78 \times 50}{100}=39$
$B=\frac{65 C}{100}=\frac{65 \times 50}{100}=32.5$
Therefore, required value of $2 C-4 B+A$
$
=2 \times 50-4 \times 32.5+39
$
$
=100-130+39
$
$
=9
$
If x% of 180 is 25% less than (x + 350), then 18% of (x + 50) is what percentage more than 12% of x?
According to the question,
x =
x = 250
Now, the value of 18% of (x + 50) == = 54
The value of 12% of x = = 30
Therefore, required percentage == = 80%
Hence, option D is correct.
The price of petrol shot up by $5\%$. Before the hike, the price of petrol was ₹82 per litre. A man travels $3045 \mathrm{~km}$ every month and his car gives a mileage of $15 \mathrm{~km}$ per liter. What is the increase in the monthly expenditure (to the nearest ₹) on the man's travel due to the hike in the petrol prices?
Clearly, quantity of petrol required to travel
$3045 \mathrm{~km}=\frac{3045}{15}$$=203$ litres
Now, increase in price of petrol per litre = 82 $\times \frac{5}{100}$
= 4.1 rupees
So, required increase in monthly expenses on petrol
= 203 × 4.1 = 832.3
$\approx 832$ rupees
$\left(x \times \frac{45}{100}\right)+\left(90 \times \frac{30}{100}\right)=\left(210 \times \frac{30}{100}\right)+\left(x \times \frac{20}{100}\right)$
$\Rightarrow \quad \frac{1}{100}[45 x]+[2700]=[(6300)+(20 x)] \times \frac{1}{100}$
$\Rightarrow \quad 45 x-20 x=6300-2700$
$\Rightarrow \quad 25 x=3600$
$\Rightarrow \quad x=\frac{3600}{25}$
$=144$
$x-15=x-x \times \frac{80}{100}$
$\Rightarrow \quad x-15=x\left(1-\frac{80}{100}\right)=x\left(\frac{20}{100}\right)=\frac{x}{5}$
$\Rightarrow \quad 5 x-75=x$
$\Rightarrow \quad 5 x-x=75$
$\Rightarrow \quad 4 x=75$
$\Rightarrow \quad x=75 / 4$
$\therefore$ अभीष्ट उत्तर $\quad \frac{75}{4} \times \frac{40}{100}=7.5$
अंग्रेजी में अनुत्तीर्ण परीक्षार्थी $=100-70=30 \%$
गणित में अनुत्तीर्ण परीक्षार्थी $=100-80=20 \%$
दोनों विषयों में अनुत्तीर्ण परीक्षार्थी $=10 \%$
दोनों विषयों में कुल उत्तीर्ण परीक्षार्थी
$
\begin{aligned}
&=[100-(30+20-10)] \% \\
&=(100-40) \%=60 \%
\end{aligned}
$
माना कुल परीक्षार्थियों की संख्या $x$ है।
$\therefore x$ का $60 \%$
\begin{array}{ll}
\Rightarrow & \frac{x \times 60}{100}=144 \\
\Rightarrow & x=\frac{144 \times 100}{60} \\
\Rightarrow & x=240
\end{array}
माना कुल मतदाता $x$ थे। $8 \%$ मतदाताओं ने अपने मत नहीं डाले।
जीतने वाले उम्मीदवार को प्राप्त मत $=48 \%$
हारने वाले उम्मीदवार को प्राप्त मत
$\ =[100-(48+8)] \%=44 \% $
मतों का अन्तर =1100
कुल मतों की संख्या =
$ =\frac{1100}{48-44} \times 100=\frac{1100 \times 100}{4}=27500 $
यहाँ $r_{1}=20 \%, \quad x=30$
तथा $r_{2}=32 \%, \quad y=42$
$\therefore$ परीक्षा का पूर्णांक $=\frac{x+y}{r_{2}-r_{1}} \times 100$
$=\frac{30+42}{32-20} \times 100=\frac{72}{12} \times 100=600$
$\therefore$ परीक्षा के न्यूनतम अंक $=\frac{32 \times 600}{100}-42$
$=192-42=150$
$\therefore$ न्यूनतम अंकों का प्रतिशत $=\frac{150 \times 100}{600}=25 \%$