Percent, decimals and fractions
Decimal form of 100%
The decimal form of 100% is 1.
% increase from 10 to 20
The % increase from 10 to 20 is 100%
change =20-10=10
original amount=10
% increase=10/10=1=100%
% decrease from 20 to 10
The % decrease from 20 to 10 is 50%
change =20-10=10
original amount=20
% increase=10/20=0.5=50%
A fire department received 70 false alarms out of 700. What percent of alarms were not false?
METHOD 1
% false alarm is 10%
70:700=x:100
% of not false alarms is 100-10=90%
METHOD 2
Not-false alarms are 700-70=630
630:700=x:100
x = 90
% of not false alarms is 90%
What percent of 200 is 10?
10 is 5% of 200.
10:200=x:100
10 is the percentage
200 is the base
x is the percent
Fraction form of 50%.
The fraction form of 50% is 1/2.
% increase from 5 to 9
The % increase from 5 to 9 is 80%
change =9-5=4
original amount=5
% increase=4/5=0.8=80%
% decrease from 2 to 1.5
The % decrease from 2 to 1.5 is 25%
change =2-1.5=0.5
original amount=2
% increase=0.5/2=0.25=25%
Leo Messi and Cristiano Ronaldo practice penalty kicks. Messi scored 17 times out of 20 and Ronaldo scored 22 times out of 25. Who made the highest percent of penalty kicks?
Ronaldo made the highest percent of penalty kicks
Messi: 17:20=x:100, x=85=85%
Ronaldo: 22:25=x:100, x=88=88%
what number is 50% of 60?
30 is 50% of 60.
x:60=50:100
30 is the percentage
60 is the base.
Percent and fraction form of 0.2.
The percent form of 0.2 is 20% and the fraction form is 20/100, which in simplest form is 1/5.
% increase from 60 to 66
The % increase from 60 to 66 is 10%
change =66-60=6
original amount=60
% increase=6/60=1/10=0.1=10%
% decrease from 40 to 30
The % decrease from 40 to 30 is 25%
change = 40-30=10
original amount = 40
% increase = 10/40=1/4=0.25=25%
The sale tax on a 30$ item is 10%. What is the total cost?
The total cost is 33$.
sale tax = 10% of 30$ = 3$
(10:100=x:30, x = 30x10/100=30x0.1=3)
Total cost = original price + tax = 30 + 3 =33$
What is 20% of 10?
2 is 20% of 10.
x:10=20:100
x is the pecentage
10 is the base
Decimal form of 0.1%.
The decimal form of 0.1% is 0.001.
% increase from 0.1 to 0.3
The % increase from 0.1 to 0.3 is 200%
change = 0.3-0.1= 0.2
original amount = 0.1
% increase = 0.2/0.1 = 2 = 200%
% decrease from 500 to 100
% decrease from 500 to 100 is 80%
change =500-100=400
original amount=500
% increase=400/500=4/5=0.8=80%
Dinner costs 60$ and I am leaving 20% tip. How much money do I pay in total?
The total cost is 72$.
tip = 20% of 60$ = 12$
(20:100=x:60, x = 60x20/100=60x0.2=12)
Total cost = original price + tip = 60 + 12 =72$
0.5% of what number is 10?
10 is 0.5% of 2000.
0.5:100=10:x
x is the base
10 is the percentage
Fraction and decimal form of 75%.
The fraction form of 75% is 75/100, which in simplest form is 3/4.
The decimal form of 75% is 0.75.
% increase from 0.1 to 10
% increase from 0.1 to 10 is 990%
change =10-0.1=9.9
original amount=0.1
% increase=9.9/0.1=99=990%
% decrease from 0.1 to 0.01
% decrease from 0.1 to 0.01 is 90%
change =0.1-0.01=0.09
original amount=0.1
% increase=0.09/0.1=0.9=90%
An iphone costs 1000$ and it's on 20% discount. What is the discounted price?
The discounted price is 800$.
discount = 20% of 1000$ = 200$
(20:100=x:1000, x = 1000x20/100=1000x0.2=200)
Discounted price= original price - discount = 1000 -200 =800$
20 is 200% of what number?
20 is 200% of 10.
20:x=200:100
20 is the percentage
x is the base
x=10