Tutor MathsGuru: Ask me for your burning Maths questions!

[Herbie]

hi Dharma,


If the qn is silent abt the pi, it is possible for us to key into the calculator 22/7 and it is for calculation?

i dun know why but 22/7 = 3.142857143 whereas the pi the calculator is 3.141592654.

My son used 22/7 for his calculation and his school teacher marked his answer 228.38 as incorrect.

What is yr view on this???

Many thanks!

[Dharma]

Herbie:

hi Dharma,


If the qn is silent abt the pi, it is possible for us to key into the calculator 22/7 and it is for calculation?

i dun know why but 22/7 = 3.142857143 whereas the pi the calculator is 3.141592654.

My son used 22/7 for his calculation and his school teacher marked his answer 228.38 as incorrect.

What is yr view on this???

Many thanks!

If the qn is silent; then use the pi sign in the calculator.
You should use 22/7 only when the question says (pi = 22/7) or use 3.142 when qns says (pi = 3.142)

To be safe, just follow the instructions. The accuracy in the answer to decimal places may be important now with the introduction of calculators for paper 2.

Anyway, I'm just a parent. You may wish to check with your son's maths teacher on this just to be doubly sure.

[Muffins]

Dharma is completely right. For a test, I had put my answer as 60.22, because I had used 22/7, but the answer was 60.21, and I had lost the 4 marks. So, it is better to check the question before...

[Tang]

Dharma:

Yu Xuan:

[quote=\"Dharma\"]
Mass of all 5 boys
= (105 + 113 + 116 + 117 + 118 + 124 + 125 + 130 + 137 + 139)/4
= 306

Sum of the mass of the 2 lightest boys and 2 heaviest boys
= 105 + 139
= 244

The mass of the 3rd heaviest boy = 306 – 244 = 62

cracking my head on how I should proceed after getting 306.

I surelyyou.

Hi Yu Xuan,

Thanks but I am actually learning from all of you everyday and I hope that our sharing will be truly beneficial to parents and their P6 kids in this coming PSLE Maths exam.[/quote]
Hi,

A - largest, E - smallest

A + B = 139

A + C = 137

Based on answer above C = 62, so A = 137 - 62 = 75

and B = 139 - 75 = 64


E + D = 105

E + C = 113

Similarly, E = 113 - 62 = 51 and D = 105 - 51 = 54

A, B, C, D, E --> 75, 64, 62, 54, 51

However the mass of 2 are:

139, 137, 129, 126, 126, 118, 116, 115, 113 and 105

These do not tally with those numbers given in the question.

Any comments?

[super star]

hi maths guru

please help me with this problem.
Eliot can paint a room in 3 hrs.fred can paint the same room in 5 hrs.how long will they take to paint the room if they do it together?

[super star]

pls help me with this problem


fill in the blank
0.7:7/8=__ :___

[starlight1968sg]

super star:

pls help me with this problem


fill in the blank
0.7:7/8=__ :___

0.7 = 7/10 = 700/1000

7/8 = 875/1000

So the ratio is 700 : 875 = 28 : 35 = 4 : 5 :roll:

[starlight1968sg]

Tang:

Hi,


A - largest, E - smallest

A + B = 139

A + C = 137

Based on answer above C = 62, so A = 137 - 62 = 75

and B = 139 - 75 = 64


E + D = 105

E + C = 113

Similarly, E = 113 - 62 = 51 and D = 105 - 51 = 54

A, B, C, D, E --> 75, 64, 62, 54, 51

However the mass of 2 are:

139, 137, 129, 126, 126, 118, 116, 115, 113 and 105

These do not tally with those numbers given in the question.

Any comments?

I don't understand that given solution too.

[maths6a]

super star:

pls help me with this problem


fill in the blank
0.7:7/8=__ :___

Let me try:=
2 : 3 is also equal to 2 divide by 3

so 0.7 : 7/8
= 7/10 divide by 7/8
= 7/10 x 8/7
= 4/5
= 4 : 5

another way is to make to common denomintaors:
7/10 : 7/8
= 28/40 : 35/40
= 28 : 35
= 4 : 5

AM I correct?
THanks

[Almighty]

super star:

hi maths guru

please help me with this problem.
Eliot can paint a room in 3 hrs.fred can paint the same room in 5 hrs.how long will they take to paint the room if they do it together?

Hi Superstar,
Let me try:


Eliot can paint 1/3 of a room in 1 hr
Fred can paint 1/5 th of a room in 1 hr.
If they paint together:
in 1 hr they can paint 8/15 of a room
So,they will take 1 7/8 hrs to paint a room together.