Tutor MathsGuru: Ask me for your burning Maths questions!

[mathsguru]

YLH88:

Hi, need ur help with the below question :


At present, Ronald is 3 times as old as his sister. In 22 years' time, Ronald's age will be 19 years less than twice his sister's age. How old is Ronald now ?

Hi YLH88,

Please see my solution below. Hope it helps!

http://www.postimage.org/image.php?v=aV1cSFU0


MathsGuru

[kiasimom]

Hi mathsguru,


Happy 2010 to you. Hope you have fully recovered from your sickness.

We look forward to having you here at KSP to help us

Take care :celebrate:

[mathsguru]

Dad fm East:

1) At first, Jonathan had 2/3 as many stamps as Kevan. After Jonathan bought another 8 stamps and Kevan lost 5 stamps, Jonathan now has 4/5 as many stamps as Kevan. Find the number of stamps Jonathan had at first.


2)At a school carnival, there were 520 more girls than boys. 1/8 of the girls and 1/5 of the boys left the carnival. In the end, there were 488 more girls than boys.
a) How many more girls left?
b) How many children were there in the carnival at the end?

Hi Dad fm East,

Here you go...hope the diagrams are clear enough for you and your ds to understand!

http://www.postimage.org/image.php?v=aV1dbZui

http://www.postimage.org/image.php?v=aV1dbW_9

Cheers,
MathsGuru

[mathsguru]

parentof3:

The cost of 3 similar watches and 4 similar rings is $218. Nancy bought 4 such watches and 3 such rings for $342. What is the cost of 2 such watches and 3 such rings.

Hi Parentof3,

Apologies but I can't seem to solve this question. If I'm not wrong, the question probably has an error because I can't obtain 2 positive answers for the prices. My answer is $102 for 1 watch and -$22 for 1 ring which is not logical. In any case, using the answers above, 2 watches and 3 rings will cost $$138.

Any one else who can solve this without ending up with a negative answer? Will be really insightful to see the solution!


MathGuru

[mathsguru]

kiasimom:

Hi mathsguru,


Happy 2010 to you. Hope you have fully recovered from your sickness.

We look forward to having you here at KSP to help us

Take care :celebrate:

Thanks alot Kiasimom! Still coughing a little, but at least I see signs of recovery already. Water is my best friend, especially since I have to talk alot during lessons...haha...

Happy 2010 to you too!

Cheers,
MathsGuru

[trytry]

Before


girls [5u+65][5u+65][5u+65][5u+65][5u+65][5u+65][5u+65][5u+65]


boys [8u ][8u ][8u ][8u ][8u ]----------------------520--------------------

(split the boys into 40 units and rearrange the girls as above)



After

girls [5u+65][5u+65][5u+65][5u+65][5u+65][5u+65][5u+65]


boys [8u ][8u ][8u ][8u ]--------------------488-------------------



girls: 5ux7 + 65x7 = 35u + 455

boys: 8ux4 =32u

35u + 455 -32u = 488

3u = 488-455
= 33
1u = 33 / 3 = 11

Total children at the end= 32u + 35u + 455
= 67u + 455
= 67x11 + 455
= 737 +455
= 1192


easier to understand?

mathsguru:

Dad fm East:

1) At first, Jonathan had 2/3 as many stamps as Kevan. After Jonathan bought another 8 stamps and Kevan lost 5 stamps, Jonathan now has 4/5 as many stamps as Kevan. Find the number of stamps Jonathan had at first.

2)At a school carnival, there were 520 more girls than boys. 1/8 of the girls and 1/5 of the boys left the carnival. In the end, there were 488 more girls than boys.
a) How many more girls left?
b) How many children were there in the carnival at the end?

Hi Dad fm East,

Here you go...hope the diagrams are clear enough for you and your ds to understand!

http://www.postimage.org/image.php?v=aV1dbZui

http://www.postimage.org/image.php?v=aV1dbW_9

Cheers,
MathsGuru

[YLH88]

Hi Mathsguru,


Thank you for the explanation and solution.

Hope you have fully recovered

[Dharma]

mathsguru:

parentof3:

The cost of 3 similar watches and 4 similar rings is $218. Nancy bought 4 such watches and 3 such rings for $342. What is the cost of 2 such watches and 3 such rings.

Hi Parentof3,

Apologies but I can't seem to solve this question. If I'm not wrong, the question probably has an error because I can't obtain 2 positive answers for the prices. My answer is $102 for 1 watch and -$22 for 1 ring which is not logical. In any case, using the answers above, 2 watches and 3 rings will cost $$138.

Any one else who can solve this without ending up with a negative answer? Will be really insightful to see the solution!


MathGuru

Hi mathsguru,

You’re right …. there's an error in qn. Think the cost of 3 watches & 4 rings should be $281 instead of $218.

3W + 4R = 281
4W + 3 R = 342
7W + 7R = 623
1W + 1R = 89
1R = 281 – 3(89) = 14
1W = 89 – 14 = 75

So, 2W + 3R = 2(75) + 3(14) = 192

Cost of 2 watches & 3 rings will be $192.

[parentof3]

Dharma:

Hi mathsguru,


You’re right …. there's an error in qn. Think the cost of 3 watches & 4 rings should be $281 instead of $218.

3W + 4R = 281
4W + 3 R = 342
7W + 7R = 623
1W + 1R = 89
1R = 281 – 3(89) = 14
1W = 89 – 14 = 75

So, 2W + 3R = 2(75) + 3(14) = 192

Cost of 2 watches & 3 rings will be $192.

Thanks dharma & mathsguru!

[Dad fm East]

mathsguru:

Dad fm East:

1) At first, Jonathan had 2/3 as many stamps as Kevan. After Jonathan bought another 8 stamps and Kevan lost 5 stamps, Jonathan now has 4/5 as many stamps as Kevan. Find the number of stamps Jonathan had at first.


2)At a school carnival, there were 520 more girls than boys. 1/8 of the girls and 1/5 of the boys left the carnival. In the end, there were 488 more girls than boys.
a) How many more girls left?
b) How many children were there in the carnival at the end?

Hi Dad fm East,

Here you go...hope the diagrams are clear enough for you and your ds to understand!

http://www.postimage.org/image.php?v=aV1dbZui

http://www.postimage.org/image.php?v=aV1dbW_9

Cheers,
MathsGuru

Hi MathsGuru,
Glad you are back. Thanks for your help. :thankyou: :lol: