TTO ch7 lesson 17

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 1

What percent is coloured?

1. 50%
2. 60%
3. 75%
4. 80%

Fraction --> percentage
3/5 equals...

1. 75%
2. 55%
3. 60%
4. 50%

What percent equals 0,87?

1. 8,7%
2. 87%
3. 0,87%
4. 870%

Fraction --> Percentage

​4​​1​​

1. 1:4
2. 25%
3. 0,25
4. 0,75

Instruction

• If you need to find a ⁣portion of the total, then you have to calculate the ⁣percent. ⁣
  
• If you need to find a ⁣part of the whole, then you have to calculate the ⁣amount.
  
• If you need to find the ⁣whole, then you have to calculate the ⁣base value.

Instruction

• For example: 
• During a traffic check, the police checked the lights of 120 cars and found that ⁣15 %⁣ of them had defects. A total of 18 cars failed the inspection.
• Base: ⁣120 cars (equals ⁣100 %)
• Amount: 18 cars
• Percent: ⁣15 %

What is the amount in this scenario?
A bag costs £75 normally, but with 33,3% discount, it costs £50 now.

1. £75 is the amount.
2. 33,3% is the amount.
3. £25 is the amount.
4. £50 is the amount.

Formulas to know

• To find the base value: 
• Amount : percent x 100
• To find the amound: 
• Base value : 100 x percent
• To find the percent: 
• Amout : base value x 100

• 12 students (out of 26) are girls. What percent of the class is a girl? 
• 12 : 26 x 100 = 46,2 % 
• You get 12 euro discount on a tablet. This equals 4%. What was the original price? 
• 12 : 4 x 100 = 300 e 

There are 1935 students at school. There are 28 students in the "HV brugklas".
What percent is in the "HV brugklas"?
Use your calculator.

1. 1,4%
2. 2,8%
3. 28%
4. 14,5%

There were 2 students late today. There are 31 students in the class. What percent of the students in the class was too late?

1. 5%
2. 6,5%
3. 7,5%
4. 10%

There are 31 students in the class. 30% of them doesn't live in Zwolle. How many students don't live in Zwolle?

1. 9 students
2. 10 students
3. 11 students
4. 12 students

To do: 

4.1 & 4.2 in bettermarks