Tutor MathsGuru: Ask me for your burning Maths questions!

[MathIzzzFun]

violet04:

MathIzzzFun:

[quote=\"violet04\"]Hi,

Please help with the following P3 question. Thanks!

Find the smallest number such that it leaves a remainder of 3 when divided by 5 and leaves a remainder of 5 when divided by 7.

Hi

the standard method for solving this type of questions is using the listing method.

List out the multiples of 5 & 7 and add the remainder and find the smallest number that matches.

5 --> 5, 10, 15, 20, 25, 30, 35, 40
+3 --> 8, 13, 18, 23, 28, 33, 38, 43

7 --> 7, 14, 21, 28, 35, 42
+5 --> 12, 19, 26, 33, 40, 47

From above, we see that 33 is the lowest number that matches.

A quicker method is to see that by adding 2 to the number it will be divisible by both 5 & 7 (divide by 5 --> remainder 3, so add 2, the number is divisible by 5; divide by 7 --> remainder 5, add 2 and the number is also divisible by 7). So, the smallest number that is divisible by both 5 & 7 is 5 x 7 = 35. Since we have added 2, the number is 35 - 2 = 33.

Using this method, subsequent numbers that meet the above conditions are :
35 x 2 - 2 = 68
35 x 3 - 2 = 103
35 x 4 - 2 = 138
.....

cheers.

Hi MathIzzzFun,
Thank you very much of the solution. Cheers![/quote]u r welcome

cheers!

[imacsg]

Pls help.

What is the difference between prism and pyramid?
Thanks.

[MathIzzzFun]

imacsg:

Pls help.

What is the difference between prism and pyramid?
Thanks.

Hi

Prism will normally have two flat parallel surfaces, whereas pyramid always have a vertex - see image below :

http://i43.tinypic.com/xwdy.jpg\">

cheers.

[violet04]

Hi,

Please help with the following another P3 question. Thanks!

Mrs Singh has a certain number of sweets to distribute to her class. If she gives each of them 5 sweets, she will have 54 extra sweets. If she gives each of them 8 sweets, she would need another 33 more. How many children does she have in her class?

[kwcllf]

violet04:

Hi,

Please help with the following another P3 question. Thanks!

Mrs Singh has a certain number of sweets to distribute to her class. If she gives each of them 5 sweets, she will have 54 extra sweets. If she gives each of them 8 sweets, she would need another 33 more. How many children does she have in her class?

You can use guess and check method. But the faster way is this:

54 sweets- 33 sweets = 21 sweets

Difference between 5 & 8 sweets = 3 sweets

Therefore, No. of children is 21/3 = 7 children.

[violet04]

Hi kwcllf,

Thks for your assistance. But the answer is 29 children…quite puzzle.

[MathIzzzFun]

violet04:

Hi,

Please help with the following another P3 question. Thanks!

Mrs Singh has a certain number of sweets to distribute to her class. If she gives each of them 5 sweets, she will have 54 extra sweets. If she gives each of them 8 sweets, she would need another 33 more. How many children does she have in her class?

Hi

a similar question was discussed here - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=67&t=25121&start=70

cheers.

[kwcllf]

violet04:

Hi kwcllf,

Thks for your assistance. But the answer is 29 children...quite puzzle.

Hi Violet04,

Sorry. I read the question wrongly that Mrs Singh has extra 33 sweets. If she is short of 33 sweets instead, the correct answer is 29 children.

54 + 33 = 87 sweets

Difference between 5 & 8 sweets = 3 sweets

Therefore, No. of children = 87/3 = 29 children.

[violet04]

kwcllf:

violet04:

Hi kwcllf,

Thks for your assistance. But the answer is 29 children...quite puzzle.

Hi Violet04,

Sorry. I read the question wrongly that Mrs Singh has extra 33 sweets. If she is short of 33 sweets instead, the correct answer is 29 children.

54 + 33 = 87 sweets

Difference between 5 & 8 sweets = 3 sweets

Therefore, No. of children = 87/3 = 29 children.

Hi kwclif,
Thks for the guidance.

[violet04]

MathIzzzFun:

violet04:

Hi,

Please help with the following another P3 question. Thanks!

Mrs Singh has a certain number of sweets to distribute to her class. If she gives each of them 5 sweets, she will have 54 extra sweets. If she gives each of them 8 sweets, she would need another 33 more. How many children does she have in her class?

Hi

a similar question was discussed here - http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=67&t=25121&start=70

cheers.

Hi MathIzzzFun,
Thks for the info. Sorry i m quite new @burning maths question.