The word 'percent' literally means 'out of a hundred.' Percentages, like fractions and decimals, are used in mathematics to describe components of a whole. When working with percentages, the entire is divided into one hundred equal pieces.
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How to Calculate Percentages:
Calculate the Off/Added Percentage:
Most percentage tests will need you to execute one of two calculations: % added or percentage subtracted.
You'll need to know the % added if you're figuring out how much gratuity you should pay. That is, you will calculate a percentage of what you paid and pay that amount in addition to the principle.
So, if you paid $26 for a lunch and wanted to tip 15%, you would multiply 26*.15 to get 3.9 and then pay $3.90. To incorporate the original amount, we may simplify this operation by swapping 1.15 for.15. In such scenario, multiply 26 by 1.15 to arrive at 29.90, which is your total.
However, it's possible that you're calculating % off. You'll need to know how to remove a percentage from the principal amount if you're paying with a coupon. Assume you have a voucher for a 15% discount on a $18 movie theatre ticket. To obtain 2.7, multiply 18*.15 and deduct $2.70 from the result. However, if you have a 15% discount coupon, you should be aware that you are only paying 85%, in which case you may just multiply 18*.85 to get your total
price straight immediately.
Percentage Increase/Decrease Calculation:
You may be required to compute % increases or decreases on occasion. Use caution while employing the strategies outlined above. This is a unique situation that necessitates a unique formula. You'll need to use the following formula to calculate the percentage increase or decrease:
*100 (old-new)/(old)
Let's put this to the test. Imagine Crispy Chips decided to save money by putting 15% fewer chips in each bag. What is the weight of the bag now, if they started with 50g?
(50-x)/(50)*100=15
(50-x)/(50)=.15
50-x=7.5
x=42.5g
You may use the same formula to raise by a percentage. Simply enter the numbers and solve as usual. Increase/Decrease in Percentage:
Questions and answers;
Question 1:
The percentage of metals in a mine of lead ore is 60%. Now the percentage of silver is 3/4% of metals and the rest is lead. If the mass of ore extracted from this mine is 8000kg. The mass (in kg) of lead is:
Option 1: 4763
Option 2: 4764
Option 3: 4762
Option 4: 4761
Answer:
2: 4764
Explanation:
Let the mass of lead be 100 units. Then, Metals = 60 unit
Silver in the metal = 60 x (3/(4x100)) = 9/20 unit
Lead in the metal = 60 - 9/20 = (1200 - 9)/20 = 1191/20 units According to the question, 100 units represent 8000 kg. 1 unit=80kg.
1191/20 unit = 80 x (1191/20) =4x1191=4764kg.
Question 2:
(0.756 x 3/4) terms of rate percent is equivalent to?
Option 1: 50.7%
Option 2: 54.7%
Option 3: 53.7%
Option 4: 56.7%
Answer:
4: 56.7%
Explanation:
(0.756 x 3/4) = (756/1000) x (3/4) x 100 % = 56.7%
Question 3:
? x 15 = 37.5% of 220
Option 1: 5.5
Option 2: 5.6
Option 3: 5.25
Option 4: 5.05
Answer:
1: 5.5
Explanation:
Let N x 15=37.5%of220
⇒ 15N =(37.5 x 220) / 100 ∴N=(37.5x220)/(100x15)=5.5
Question 4:
The number .05 is how many percent of 20 ?
Option 1: 25
Option 2: 0.25
Option 3: 0.025
Option 4: 0.0025
Answer:
2: 0.25
Explanation:
Lety%of 20=.05 Then, (y x 20)/100 = .05 ∴y=.25
Question 5:
What is 25% of 25% equal to?
Option 1: 0.0625
Option 2: 0.625
Option 3: 0.00625
Option 4: 0.000625
Answer:
2: 0.625
Explanation:
25% of 25% = (25/100) x (25/100) = 625/10000 = 0.625
Question 6:
? % of 250 + 25% of 68 = 67
Option 1: 10
Option 2: 15
Option 3: 20
Option 4: 25
Answer:
3: 20
Explanation:
Let Y% of 250 + 25% of 68 = 67 ⇒ (Y x 250)/100 + (25 x 68)/100 = 67 ⇒ 5Y/2 = 50 ∴ Y = (50 x 2) / 5 = 20
Question 7:
30% of 140 = ? % of 840 ?
Option 1: 5
Option 2: 10
Option 3: 15
Option 4: 20
Answer:
1: 5
Explanation:
Let y % o f840 = 30 % of 140
⇒ (y/100) x 840 = (30/100) x 140
∴y=(30x140x100)/(100x840)=5
Question 8:
The fraction equivalent to 2/5% is ?
Option 1: 1/25
Option 2: 1/5
Option 3: 1/125
Option 4: 1/250
Answer:
4: 1/250
Explanation:
2/5% = (2/5) /100 = 1/250
Question 9:
?%of130=10.4?
Option 1: 8
Option 2: 80
Option 3: 0.8
Option 4: 0.08
Answer:
1: 8
Explanation:
Let Y % of 130=10.4 ⇒(Yx130)/100=10.4 ∴Y=(10.4x100)/130=8
Question 10:
What percent of 7.2 kg is 18 gms ?
Option 1: 2.5%
Option 2: 25%
Option 3: 0.25%
Option 4: 0.025%
Answer:
3: 0.25%
Explanation:
.2 kg = 7.2 x 1000000 gm = 7200000 gms
Required percentage = (18/7200000) x 100 % = 0.25%
Question 12:
.025 in terms of rate of rate per cent is ?
Option 1: 0.25%
Option 2: 2.5%
Option 3: 0.025%
Option 4: 25%
Answer:
2: 2.5%
Explanation:
.025 = (25/1000) x 100% = 2.5%
Question 13:
At an election there were two candidates. A candidate got 38% of the vote and lost by 7200 votes. The total number of valid votes were
Option 1: 16200
Option 2: 30000
Option 3: 13000
Option 4: 13800
Answer: 2: 30000
Explanation:
Question 14:
If 8% of x = 4% of y,then 20% of x is
Option 1: 40% of y
Option 2: 80% of y
Option 3: 10% of y
Option 4: 16% of y
Answer:
3: 10% of y
Explanation:
Question 15:
The ratio between the ages of Ram and Rahim is 10:11. What% of Ram's age is Rahim's age?
Option 1: 109 1/11 %
Option 2: 110%
Option 3: 111 1/9%
Option 4: 111%
Answer:
2: 110%
Explanation:
Required Percentage = 11×100/10=110% So, The correct option is 2.
Question 16:
If the radius of a sphere be doubled, then the percentage of increase in volume is
Option 1: 600%
Option 2: 800%
Option 3: 500%
Option 4: 700%
Answer 4: 700%
Explanation:
Question 17:
51% of the whole number is 714. 25% of that number is
Option 1: 450
Option 2: 550
Option 3: 250
Option 4: 350
Answer:
4: 350
Explanation:
Question 18:
A man gives 50% of his money to his son and 30% to his daughter. 80% of the rest is donated to a trust. If he is left with ` 16,000 now, how much money did he have in the beginning?
Option 1: 8,00,000
Option 2: 4,00,000
Option 3: 40,000
Option 4: 80,000
No answer is set
Explanation:
Question 19:
The population of a town increases by 5% every year. If the present population is 9261, the population 3 years ago was
Option 1: 5700
Option 2: 6000
Option 3: 7500
Option 4: 8000
Answer:
4: 8000
Explanation:
Population 3 yrs. Ago
Question 20:
The price of cooking oil increased by 25%. Find by how much percentage a family must reduce its consumption in order to maintain the same budget?
Option 1: 70%
Option 2: 20%
Option 3: 30%
Option 4: 80%
Answer:
2: 20%
Explanation: