Math Is Fun Virtual Manipulative

Some Challenge probability problems

1. A large basket of fruit contains 3 oranges, 2 apples and 5 bananas. If a piece of fruit is chosen at random, what is the probability of getting an orange or a banana? 
  
Solution:


Oranges = 3
Apples = 2
Bananas = 5

Total = 10

As they've asked either orange or banana, we ADD the probability.

Probability of orange + Probability of banana

3/10  +  5/10 = 8/10

                     = 4/5


2. In a class of 30 students, there are 17 girls and 13 boys. Five are A students, and three of these students are girls. If a student is chosen at random, what is the probability of choosing a girl or an A student?

Solution:

Girls = 17
Boys = 13

A grade students = 5
Out of which, girls = 3 and boys = 2
So, 17 - 3 = 14 girls are not A grade students.

Therefore, probability of getting a girl or an A student:

14/30  +  5/30  = 19/30

3. In the United States, 43% of people wear a seat belt while driving. If two people are chosen at random, what is the probability that both of them wear a seat belt? 

 Solution:

The probability a person who wears a seat belt is selected = 43/100.

The probability that both of them wear a seat belt  is :
43/100 * 43/100 = 1849/10000
                           = 18%

4. Three cards are chosen at random from a deck without replacement. What is the probability of getting a jack, a ten and a nine? 

Solution:


There are 52 cards in a pack. There are 4 suits i.e. clubs, spades, hearts and diamonds.

Hence, there will be 4 jacks, 4 tens and 4 nines.

Since the cards are selected WITHOUT replacement the total no. of cards will decrease by one each time. Hence,

4/52 * 4/51 * 4/50 = 8/16575

5. A city survey found that 47% of teenagers have a part time job. The same survey found that 78% plan to attend college. If a teenager is chosen at random, what is the probability that the teenager has a part time job and plans to attend college? 

Solution:


47/100 * 78/100 = 1833/5000=37%

6. In a school, 14% of students take drama and computer classes, and 67% take drama class. What is the probability that a student takes computer class given that the student takes drama class? 

Solution:


Drama = 67/100

Computer and Drama = 14/100

Hence, 67/100 * x = 14/100

Therefore, x = 14/67 
                      =21 %

7. In a shipment of 100 televisions, 6 are defective. If a person buys two televisions from that shipment, what is the probability that both are defective?
 Solution:


Defective TVs = 6

Total = 100

As the person buys two tvs, one out of hundred and one out of 6 gets subtracted, meaning:

6/100  *  5/100 

= 30/9900
=1/330

Sec 2 past year paper for practice

 http://www.ziddu.com/download/10763255/sec2-chungchengsa2-mathsedited.pdf.html

http://www.ziddu.com/download/10763256/S2E_Mid-Yr_Ex_P1.pdf.html

http://www.ziddu.com/download/10763257/S2E_Final_Ex_P1.pdf.html

http://www.ziddu.com/download/10763258/sec2-bp-mathsedited.pdf.html

http://www.ziddu.com/download/10763259/S2E_Final_Ex_P2.pdf.html

http://www.ziddu.com/download/10763260/S2E_Mid-Yr_Ex_P2.pdf.html

P6 past year paper practice

http://www.ziddu.com/download/10762997/Practise_3_-_2009edited.pdf.html

http://www.ziddu.com/download/10762998/Practise_2_-_2009edited.pdf.html

http://www.ziddu.com/download/10762999/Practise_1_-_2009edited.pdf.html

http://www.ziddu.com/download/10763000/Practise_Paper_1_-_SA1_2009edited.pdf.html

Practise_1_-_2009edited.pdf  (453.79 KB)

File Practise_2_-_2009edited.pdf (302.91 KB)

Pyramid problem sum

Question: The diagram shows a solid which is composed of a pyramid VABCD and a cuboid ABCDEFGH. ABCD is a square of side 8cm, VD is the height of the pyramid, which is 6cm and CG =12 cm. find


(a) the volume of the solid (done!)

(b) the total surface area of the solid.
 
Click Here to see Diagram
 
Answer:
 
 

Click Here To Download .pdf