Q&A - P5 Math

[ksmama]

ksmama:

Hi Lizawa, tks! I was trying to see how to use d 4 boys' info to solve the prob but was indeed baffled. Will see if school uses another method when my boy goes back to school, then share info.


Ano prob here
A bag has 200 blue beads and 540 yellow beads. A tin has 850 blue beads and 350 yellow beads. Some blue and yellow beads are transferred from the tin to the bag. When that is done the percentage of blue beads in the bag bcom 50% and that of blue beads in the tin bcom 70%. How many blue and yellow beads are transferred?

Hi, worked out soln to share
7u + 1p =1050--------(1)
3u + 1p =890----------(2)
4u = 160
1u =40
7u=280
3u=120
therefore, no blue beads transf =850-280=570
no yellow beads transf = 350-120=230

[tianzhu]

Chan09:

Not sure whether answers are right for these : Ai Tong 2010

1) 40 children in class sold average of 19 tickets. There were 8 more boys than girls in the class. The ave number of tickets sold by the boys was 15. Find the ave number of tickets sold by girls?
Ans: 25

2) Agnes made some fruit pies. She gave some of them to neighbor and collected $14.40 after selling 3/5 of the remaining pies for $1.20 each. She then had 1/5 of the original number of pies left. How many pies did she give to neighbor ?
Ans: 20

Hi

For Q1

40*19 ------- 760

Boys ----- 24
Girls ----- 16

24*15 ----- 360
760 – 360 ----- 400

400/16 ----- 25

For Q2, I think ‘each” is missing from the sentence as highlighted.

You may use MD.

Draw a big rectangular box. Cut 1 part and divide remaining portion into five smaller units of same size.

Number of pies sold ------ 14.4/1.2 ----- 12

3 units ----- 12
1 unit ----- 4

2 units ------ 8

1/5 of original number of pies ----- 8

Number of original number of pies ------ 5*8 ------ 40

Number of pies given to neighbour ------ 40 - 12 - 8 ------ 20

Best wishes

[tianzhu]

YumYum:

AiTong SA2, Qn 17 (Paper 2)


Hi, I need help with the foll Qn:

A seamstress had some white and black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first? (Ans : 72)

Hi

Perhaps, some information may be missing in your question.

I think there will be multiple answers.

72 is one of many possible answers.

Different after ratios which satisfy the condition (40% of the total) will give a different answer.

Now compare the original question with this one.

40% of the animals on a farm were chickens and the rest were ducks. When another 104 chickens and ducks were bought, the number of chickens was increased by 20% and the number of ducks was increased by 30%.
(a) Find the number of chickens on the farm at first, and
(b) the number of ducks on the farm after the increase.

Best wishes

[Bunny27]

Hi, pls help:


This question:
Hafizan had a packet of red jelly beans and a packet of purple jelly beans. The number of red jelly beans is thrice the number of purple jelly beans. Hafizan eats 3 red jelly beans and 2 purple jelly beans from the packets each time. After a few rounds, there are 81 red jelly beans and 8 purple jelly beans left. What is the total number of jelly beans Hafizan has?

Thanks!

Suz855:

Moderator's Note: Please use this thread to ask for help on specific questions. Please refrain from out of topic chatter in this thread to make it easier for the community to find the answers they need.

Pls help, thanks


http://i937.photobucket.com/albums/ad214/suz855/areaoftriangle-1.gif\">

:?

[YumYum]

tianzhu:

YumYum:

AiTong SA2, Qn 17 (Paper 2)


Hi, I need help with the foll Qn:

A seamstress had some white and black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first? (Ans : 72)

Hi

Perhaps, some information may be missing in your question.

I think there will be multiple answers.

72 is one of many possible answers.

Different after ratios which satisfy the condition (40% of the total) will give a different answer.

Now compare the original question with this one.

40% of the animals on a farm were chickens and the rest were ducks. When another 104 chickens and ducks were bought, the number of chickens was increased by 20% and the number of ducks was increased by 30%.
(a) Find the number of chickens on the farm at first, and
(b) the number of ducks on the farm after the increase.

Best wishes

thank you for the comparison & additional Qn.

[YumYum]

Hi, one more Qn:


Mrs Lim bought some bowls and plates. If she buys another 5 bowls, there are 60% as many bowls as plates. If she buys another 9 plates, there will be thrice as many plates as bowls. How many bowls did she buy?

Thanks!

[MathIzzzFun]

Bunny27:

Hi, pls help:


This question:
Hafizan had a packet of red jelly beans and a packet of purple jelly beans. The number of red jelly beans is thrice the number of purple jelly beans. Hafizan eats 3 red jelly beans and 2 purple jelly beans from the packets each time. After a few rounds, there are 81 red jelly beans and 8 purple jelly beans left. What is the total number of jelly beans Hafizan has?

Thanks!

Hi

Work backwards-
total = eaten + left

Total, Red : Purple = 3:1 = 3u + 81 : 2u + 8
So, 3u + 81 = 6u + 24
3u = 57, 1u = 19

Total jelly beans = 3u +81+2u+8 = 5 x19 + 89 = 184

info (horizontal dimension) is missing for the triangle question. Also, the area ratio given is wrong - I presume RS is the base of the triangle. By similar triangles, the area of the triangle PRS to shaded area = 16: 15

cheers.

[MathIzzzFun]

YumYum:

Hi, one more Qn:


Mrs Lim bought some bowls and plates. If she buys another 5 bowls, there are 60% as many bowls as plates. If she buys another 9 plates, there will be thrice as many plates as bowls. How many bowls did she buy?

Thanks!

Hi

If Mrs Lim buys 5 more bowls, bowls:plates = 3u : 5u
Total, bowls : plates = 3u -5 : 5u

If Mrs Lim buys 9 plates,
bowls : plates = 3u-5 : 5u +9 = 1 : 3
So, 9u - 15 = 5u + 9, 4u = 24, 1u =6

Number of bowls Mrs Lim bought = 3u-5 = 3x6 - 5 = 13

cheers.

[teachingmum]

http://i52.tinypic.com/2hnusdh.jpg\">

[Bunny27]

Sorry another question needs help;


Meiling puts some money in boxes P,Q,R and S. The amount of money in box P is 1/2 of the amount in boxes Q,R and S. The amount of money in box Q is 1/5 of the total amount of money in boxes P,R and S. The amount of money in box R is 1/6 of the total amount of money in P,Q and S. If there is $135 in box S, what is the total amount of money in the four boxes?

Thanks