Math Blog Post (Handphone Plans)

y= total cost
x= # of text messages

a) Determine the cost of each plan if you send 500 text messages in one month. Show your working out.

PLAN A
y=29.95+0.1x

y= 29.95+0.1(500)

y= 29.95+50

y=79.95

Plan A's cost would be $79.95 if we send 500 text messages per month.

PLAN B
y= 90.20

Since Plan B gives unlimited text messages, the cost would be $90.20 per month even for 500 text messages.

PLAN C
y=49.95+ 0.5x
y= 49.95+0.05(500)
y= 49.95+ 25
y= 74.95

Plan C's total cost would be $74.95 if we send 500 text messages per month.


b) Your boss asks you to visually display three plans and compare them so you can point out the advantages of each plan to your customers

Plan A would be beneficial and practical for those who know they rarely text message. That way the basic fee plus only a few text messages could turn out a cheaper deal in a certain situation. (Plan A is the red line)


For Plan B, an advantage is that it allows unlimited text messages, so for those who text a lot, Plan B would be a good deal. (Plan B is the blue line)

For Plan C, an advantage is that the basic fee of $49.95 is just an additional $20 (less than half the amount), and the charge of cents per text message is half the amount. On the graph, plan C is the green line, and we can see that we can text more messages than Plan A for the same price.

c) A customer wants to know how to decide which plan would save her the most money. Determine which plan has the lowest cost given the number of text messages a customer is likely to send. 

PLAN A
y=29.95+0.10x

y= 29.95+0.10(2000)

y= 29.95+200

y= 229.95

Since the average number of text messages sent by adults in their early twenties are 2,000, the cost for sending 2,000 text messages is $229.95.

PLAN B
y= 90.20

The cost for 2,000 text messages still remains $90.20 because Plan B allows unlimited text messages.


PLAN C
y=49.95+ 0.05x
y= 49.95+0.05(2000)
y= 49.95+ 100
y= 149.95

The cost for sending 2,000 text messages is $149.95 with Plan C.

Plan B has the lowest cost, charging only a basic fee of $90.20 and no additional charge per text message.

Seasons on Earth

1. When I went to  Australia this winter break we went camping.  Why was the temperature never as hot as it is in Singapore?

Because the sun's rays weren't shining as directly on Australia than Singapore, since Singapore is located very near the equator and the sun shines directly on the equator, therefore Singapore has a hotter climate with more direct sunlight. Australia doesn't have as direct sunlight as it isn't as close to the equator as Singapore is.

2. My friends went to Europe snow skiing during the winter break how could this be?

Since the earth is slightly tilted, and Europe is in the Northern Hemisphere, the sun light doesn't shine as much as on the Southern Hemisphere.

3.) During the summer break I spend my time in Holland.  The sun does not set until 12;00 at night and rises around 5:00 and yet during the winter time my dutch friends complain how they hardly see sunshine,  Explain.

During summertime, Holland gets direct sunlight, but as the earth rotates, by wintertime, the sunlight isn't able to reach Holland.

4. If you were to explain to a Singaporean who has never left the country what spring and fall were what would you say?  Why does this happen and why not in Singapore?

Spring and fall happen when the sunlight from the Northern Hemisphere and Southern Hemisphere slowly goes away or slowly comes back. If the Southern Hemisphere has more light, then it experiences fall as the sunlight shines brighter in the Northern Hemisphere. This doesn't happen in Singapore because Singapore lies on the equator therefore gets the same amount of sunlight every time.

Seasons

Synopsis: The closer the place is to the equator, the hotter the climate. Daylight varies as to how direct the the sunlight shines on the place. The temperature is cooler when farther away from the sunlight and equator since the equator receives direct sunlight. That is also why places like Singapore have a hot climate since its location is very near the equator, and it never faces a cold climate.

Power of Ten

10 power 1 meters: Saguaro Cactus

10 power -2 meters: Glass Marble

10 power -4 meters: Width of Human Hair

10 power -8 meters: DNA

10 power -10 meters: Water Molecule

10 power 3 meters: Angel Falls

10 power 5 meters: Brunei

10 power 7 meters: Earth

10 power 10 meters: Total Human Height

10 power 18 meters: Omega Centauri

10 power 22 meters: Distance to the Andromeda Galaxy

                                         Not exact