What is percent ?
In mathematics, a percentage is a number or ratio that can be expressed as a fraction of 100. If we have to calculate percent of a number, divide the number by whole and multiply by 100.
Hence, the percentage means, a part per hundred. The word per cent means per 100. It represented by the symbol “%”
Example 1 :
250% of 65 is what number?
Solution :
Let x be a number.
The word ‘of’ is translated as ‘multiplication’ in math.
x = (250/100) × 65
= (16250)/100
x = 162.5
So, 250 % of 65 is162.5.
Example 2 :
50 is what percent of 40?
Solution :
Let x be a percent.
x% of 40 = 50
(x/100) ⋅ 40 = 50
4x/10 = 50
x = 500/4
x = 125%
So, 50 is 125% of 40 is 50.
Problem 1 :
A student answered 86 problems on a test correctly and received a grade 98%. How many problems were on the test, if all the problems were worth the same number of points? (Round to the nearest whole number)
Solution :
Number of questions he answered correctly = 86
Let x be the total number of questions.
98% of x = 86
0.98(x) = 86
Dividing by 0.98 on both sides.
x = 86/0.98
x = 87.75
x = 88
So, there are 88 problems.
Problem 2 :
Manuel found a wrecked Trans-Am that he could fix. He bought the car for 65% of the original price of $7200. What did he pay for the car? (Round to nearest dollar)
Solution :
Original price of the car = $7200
= 65% of 7200
= 0.65 (7200)
= 4680
He paid $4680 for the car.
Problem 3 :
Pamela bought an electric drill at 85% of the regular price. She paid $32.89 for the drill. What was the regular price? (Round to the nearest cent)
Solution :
Let x be the regular price.
85% of x = 32.89
0.85x = 32.89
Dividing by 0.85 on both sides.
x = 32.89/0.85
x = 38.69
Problem 4 :
A crew is made up of 8 men, the rest are women. 66 2/3 % of the crew are men. How many people are in the crew?
Solution :
Let x be the number of women in the crew.
Total number people (crew) = 8 + x
66 2/3% of (8 + x) = 8
200/3% of (8 + x) = 8
0.66(8 + x) = 8
5.28 + 0.66x = 8
0.66x = 8 - 5.28
0.66x = 2.72
Dividing by 0.66 on both sides.
x = 2.72/0.66
x = 4.12
So, total number of girls in the crew is 4.
Total member in the crew = 8 + 4
= 12 people are in the crew.
Problem 5 :
Ben earns $12,800 a year. About 15% is taken out for taxes. How much is taken out for taxes?
Solution :
His earning = $12800
15% of the earnings taken for tax.
= 15% of 12800
= 0.15 (12800)
= 1920
So, the tax amount is $1920.
Problem 6 :
At a sale, shirts were sold for $15 each. This price was 80% of their original price. What was the original price?
Solution :
Let x be the original price.
Selling price of shirt = $15
80% of x = 15
0.80x = 15
Dividing by 0.80 on both sides.
x = 15/0.80
x = 18.75
So, the original price is $18.75.
Problem 7 :
There are 32 students in a class. Nine of those students are women. What percent are men? (round to the nearest tenth)
Solution :
Total number of students = 32
Number of students are women = 9
Percentage of women = (9/32) x 100%
= 28.12%
= 28%
Percentage of women = 100 - 28
= 72%
Problem 8 :
The Royals softball team played 75 games and won 55 of them. What percent of the games did they lose? (round to the nearest tenth)
Solution :
Total number of games = 75
Number of games he won = 55
Number of games he lose = 75 - 55
= 20
Number of games he lose = (20/75) x 100%
= 26.6 %
So, 27% of the game they lost.
May 21, 24 08:51 PM
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