Q&A - PSLE Math

[JustKP]

Drdj:

Dear all,


Could you explain the solution of this sum from Ai Tong 2008?
The triangles are both isoceles (45, 45, 90), but I just can't seem to get it
Thanks in advance

http://www.postimage.org/image.php?v=Pq9MGnr

Hi, just joined the 2 triangles together to get an isoseles triangle of both sides 10cm (radius of the circle).

[kiasiparent]

Drdj:

Dear all,


Could you explain the solution of this sum from Ai Tong 2008?
The triangles are both isoceles (45, 45, 90), but I just can't seem to get it
Thanks in advance

http://www.postimage.org/image.php?v=Pq9MGnr

There are two smaller and unshaded triangles inside the semi circle. These two triangles can be rearranged to form a square of diagonal 10 cm.
Area of square = diagonal x diagonal / 2 = 10 x 10 / 2 = 50

Then take area of semi circle - 50

[Drdj]

Dear JustKP,


Thanks so much !!

JustKP:

Drdj:

Dear all,

Could you explain the solution of this sum from Ai Tong 2008?
The triangles are both isoceles (45, 45, 90), but I just can't seem to get it
Thanks in advance

http://www.postimage.org/image.php?v=Pq9MGnr

Hi, just joined the 2 triangles together to get an isoseles triangle of both sides 10cm (radius of the circle).

[Drdj]

Dear all,


Could you help me to solve this?
Thanks a lot
http://www.postimage.org/image.php?v=aV15TSLS

[JustKP]

Drdj:

Dear all,


Could you help me to solve this?
Thanks a lot
http://www.postimage.org/image.php?v=aV15TSLS

Angle AED is 90, so angle DAE is 27. Thus angle x is 36 (90-27-27).

[Drdj]

Thanks again

JustKP:

Drdj:

Dear all,

Could you help me to solve this?
Thanks a lot
http://www.postimage.org/image.php?v=aV15TSLS

Angle AED is 90, so angle DAE is 27. Thus angle x is 36 (90-27-27).

[suiyuan]

Thank You for your help.

Please help me solve these questions in a non-algebraic manner.

Q1) A motorist takes 1/2 h less than the usual time to travel from KTown to JTown when he increases his average speed by 10%. For a distance of 100km, he will take 1/3 h less than the usual time if his speed is 20% more than the average speed from KTown to JTown. Find the distance between KTown and JTown.

Q2) A car travels from town P to town Q at a constant speed. When it increases its speed by 20%, the journey from P to Q takes 1 hour less than its usual time. When it travels at its usual speed for 100 km before increasing its speed by 30%, the journey also takes 1 hour less than usual. Find the distance between the two towns.

[Vanilla Cake]

Sam went shopping at a department store. He spent 1/5 of his money on a sofa set and $786 on a washing machine. Later, he spent 1/8 of his remaining amount on a dining table. If the amount of money left was $86.35 more than half of the amount he had at first, how much money did Sam have at first?


:?:

[enoawng]

Dharma:

enoawng:

can anyone help?


John was n years old when his mother was 36 years old. Today, his mother is 3 times as old as John.
a) Express John’s age now in terms of n
b) What is John’s age now if n=8?

http://www.postimage.org/

Thanks.

[enoawng]

When Kumar partners Bala, they take 8 days to paint a house. When Bala partners Hashim, they take 6 days to paint the hose. When Hashim partners Muthu, they take 12 days to paint the house. How many days do Kumar and Muthu take to paint the house together?


TIA