Q&A - P5 Math

[tianzhu]

concerned1970:

Tysm Tianzhu!


Btw, can u solve this ques for me?

Hi

Kanxi is 5 times as old as Jaycee this year. Jaycee is 9 years old now.

Jaycee ------- 9
Kanxi ------- 45
Difference in age --------36

The age’s difference between two people always remains the same.

For Kanxi's age be twice that of Jaycee, Kanxi will be 72 years old and Jaycee will be 36 years old.

36 – 9 ------ 27

So the answer is in 27 years time.

Best wishes

[concerned1970]

Ty tianzhu! Now my kids have clearer picture of the explanation.


Thanks too, math freak!

[savoury sweet]

Hi


My gal had some problem in solving the two questions as below. Can anyone help?

1)Tap A can fll up a tank in 4 minutes. Tap B can fill up the same tank in 6 minutes.
How long will it take to fill up the tank if both taps are turn on at the same time?
(Ans: 2mins 24 secs)

2)When a bucket is 1/7 filled with water, its mass is 5 kg. The mass of the bucket is
25 kg when water is filled to the brim. What is the mass of the empty bucket?
(Ans: 2 kg)

Thanks so much.

[tianzhu]

savoury sweet:

Hi


My gal had some problem in solving the two questions as below. Can anyone help?

1)Tap A can fll up a tank in 4 minutes. Tap B can fill up the same tank in 6 minutes.
How long will it take to fill up the tank if both taps are turn on at the same time?
(Ans: 2mins 24 secs)

2)When a bucket is 1/7 filled with water, its mass is 5 kg. The mass of the bucket is
25 kg when water is filled to the brim. What is the mass of the empty bucket?
(Ans: 2 kg)

Thanks so much.

Hi

(1) A common multiple of 4 and 6 is 12.

Tap A
4 mins ------ 12 units
1 min ------ 3 units

Tap B
6 mins ------ 12 units
1 min ------ 2 units

In 1 min, tap A and tap B ------- 5 units

12 units ------ 10 units + 2 units

10 units ------ 2 min
2 units -------- 2/5*60 ------ 24 seconds

Total time ------ 2 mins 24 seconds.

(2) Is the number 23kg or 25kg?

Best wishes

[savoury sweet]

tianzhu:

savoury sweet:

Hi


My gal had some problem in solving the two questions as below. Can anyone help?

1)Tap A can fll up a tank in 4 minutes. Tap B can fill up the same tank in 6 minutes.
How long will it take to fill up the tank if both taps are turn on at the same time?
(Ans: 2mins 24 secs)

2)When a bucket is 1/7 filled with water, its mass is 5 kg. The mass of the bucket is
25 kg when water is filled to the brim. What is the mass of the empty bucket?
(Ans: 2 kg)

Thanks so much.

Hi

(1) A common multiple of 4 and 6 is 12.

Tap A
4 mins ------ 12 units
1 min ------ 3 units

Tap B
6 mins ------ 12 units
1 min ------ 2 units

In 1 min, tap A and tap B ------- 5 units

12 units ------ 10 units + 2 units

10 units ------ 2 min
2 units -------- 2/5*60 ------ 24 seconds

Total time ------ 2 mins 24 seconds.

(2) Is the number 23kg or 25kg?

Best wishes

Hi Tianzhu,

Thanks for your help. With regards to the 25 or 23kg, I have no idea,my gal copied down from the computer as part of the school home based learning today. She can't view the question again once submitted. She got both of the questions wrong.

If you dont mind, can you show me the work out of the qns? :oops:
Thanks a lot Tianzhu.

[tianzhu]

Hi savoury sweet


Let us use 23 kg instead of 25 kg.

You may use MD.

M ------ mass of empty bucket.

When the bucket is 1/7 filled with water (1 unit), its mass is 5 kg.

M + 1 unit ------ 5

The mass of the bucket is 25 kg when water is filled to the brim.

M + 7 units ------ 23

6 units ----- 23 - 5 ----- 18
1 unit ----- 3

Hence, M ------ 5 – 3 ------ 2

Best wishes

[savoury sweet]

tianzhu:

Hi savoury sweet


Let us use 23 kg instead of 25 kg.

You may use MD.

M ------ mass of empty bucket.

When the bucket is 1/7 filled with water (1 unit), its mass is 5 kg.

M + 1 unit ------ 5

The mass of the bucket is 25 kg when water is filled to the brim.

M + 7 units ------ 23

6 units ----- 23 - 5 ----- 18
1 unit ----- 3

Hence, M ------ 5 – 3 ------ 2

Best wishes

HI Tianzhu

Thank you so much for the explanation. Will teach my gal this method. she must have copied down the number wrongly.

[ppnadh]

1) At a funfair, there were 1/3 as many boys as girls and 2/5 as many adults as children. If there were 24 more adults than boys at the funfair, find the total number of people at the funfair.


2) Inside a bag, there were 3/5 as many red alls as blue balls and 2/3 as many green balls as blue balls. Given that there were 8 more green balls than red balls, how many balls were there in the bag altogether.

Pl help me solve these sums in detail with explanation…Thanks in advance.

[MathIzzzFun]

ppnadh:

1) At a funfair, there were 1/3 as many boys as girls and 2/5 as many adults as children. If there were 24 more adults than boys at the funfair, find the total number of people at the funfair.


2) Inside a bag, there were 3/5 as many red alls as blue balls and 2/3 as many green balls as blue balls. Given that there were 8 more green balls than red balls, how many balls were there in the bag altogether.

Pl help me solve these sums in detail with explanation....Thanks in advance.

Hi

Q1...

http://i41.tinypic.com/vybfbq.jpg\">

cheers.

[MathIzzzFun]

ppnadh:

1) At a funfair, there were 1/3 as many boys as girls and 2/5 as many adults as children. If there were 24 more adults than boys at the funfair, find the total number of people at the funfair.


2) Inside a bag, there were 3/5 as many red alls as blue balls and 2/3 as many green balls as blue balls. Given that there were 8 more green balls than red balls, how many balls were there in the bag altogether.

Pl help me solve these sums in detail with explanation....Thanks in advance.

Hi

Q2..

http://i42.tinypic.com/23m8w0n.jpg\">

you can also use ratio method for these question... for eg.
Q2.
Red : Blue --> 3 : 5 , Blue : Green --> 3 : 2
Red : Blue : Green --> 9u : 15u : 10u, total --> 34u
10u - 9u = 1u
1u --> 8, 34 x 8 = 272

cheers.