Q&A - P5 Math

[lynntan15]

mummyv:

lynntan15:

[quote=\"MathIzzzFun\"]
if 30 green apples added,
Green : Red --> 3 units + 30 : 1 unit + 10 (3:1)
number of apples,
Green : Red --> 3 units : 1 unit + 10 (Total--> 4 units + 10)
.

can elaborate further on this?

Don't really understand how 3 units + 30 : 1 unit +10? become 3 units : 1 unit + 10?

Thks very much.

hi

this is becos if 30 green apples are added ratio becomes 3:1
what MathIzzFun is doing is making the units the same with the first ration
therefore if 30 green apples are added, green apples are 3units + 30
red apples should be 1 unit +10

not sure if this helps

I also realised the method drawing explains it too

http://i46.tinypic.com/2a8omrq.jpg\">[/quote]ohic.. thks a lot for the model, help to see it much clearer

[ILOVESCIENCE]

can anyone solve this?


Mike and Vince were selling sunglasses at $12 each and $7 each respectively. Total sales collected by both was $4905. The ratio of the number of sunglasses sold by Mike to those sold by Vince is 5:7. How many sunglasses did Mike sell?

thanks!

[MANGO STAR]

small:

MANGO STAR:

Hi, need help for this MCQ question.


16/? is between 4/9 and 4/7

1) 25 2) 28 3) 30 4) 36

After changed 4/9 and 4/7 to 16/36 and 16/28 then you will know the answer is 30.

Hi small,

got it. :thankyou:

[small]

MANGO STAR,


You are welcome.

[small]

ILOVESCIENCE:

can anyone solve this?


Mike and Vince were selling sunglasses at $12 each and $7 each respectively. Total sales collected by both was $4905. The ratio of the number of sunglasses sold by Mike to those sold by Vince is 5:7. How many sunglasses did Mike sell?

thanks!

Hi.

HTH..

http://i50.tinypic.com/1fe7u8.jpg\">

[cimman]

ILOVESCIENCE:

can anyone solve this?

Mike and Vince were selling sunglasses at $12 each and $7 each respectively. Total sales collected by both was $4905. The ratio of the number of sunglasses sold by Mike to those sold by Vince is 5:7. How many sunglasses did Mike sell?
thanks!

here's a solution using the pictorial algebra approach:

http://i45.tinypic.com/8yc4z9.png\">

[usaik]

mummyv:

usaik:

Hi I need help on the following question, particularly on how to solve and get the answer for part (b).


Mrs Tan bought 4 times as many toy guns as teddy bears. She spent $1750 altogether. A toy gun cost $10 less than a teddy bear. The total cost of toy guns was $490 more than the total cost of teddy bears.
(a) how much did Mrs Tan spend on the teddy bears?
(b) How much did one teddy bear cost?

Thank you.

hi
this has been answered before by MathIzzzFun & Zack7
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=68&t=25129&start=660

Thank you so much for the link mummyv!

[sunnydays2]

Hi, I’ve got 3 questions. Please help.


1. Cherry and Lindy each saved a fixed amount of money everyday. Lindy who started saving earlier, saved $5 each day. When Lindy had saved for 12 days, Cherry had saved $27. When Lindy had saved for 31 days, Cherry had saved $84. How many days had Lindy saved when their total savings was $375?

2. Mabel has $200 more than Ben. Mabel gives 60% of her money to Ben. Ben then gives 1/4 of his money to Mabel. In the end, Ben has $200 more than Mabel. How much did Mabel have at first?

3. The ratio of the number of boys to the number of girls in a hall was 3:7. After 64 boys and 64 girls left the hall, the ratio of the number of boys to the number of girls became 2:5. Find the number of pupils in the hall at first.

[tianzhu]

sunnydays2:

2. Mabel has $200 more than Ben. Mabel gives 60% of her money to Ben. Ben then gives 1/4 of his money to Mabel. In the end, Ben has $200 more than Mabel. How much did Mabel have at first?

Hi

You may use MD or work using units.

Mabel ------- 5 units + 200
Ben -------- 5 units

After, Mabel gives 60% of her money to Ben.

Mabel ------- 2 units + 80
Ben -------- 8 units + 120

After Ben gives 1/4 of his money to Mabel.

Mabel ------- 4 units + 80 + 30
Ben -------- 6 units + 90

In the end, Ben has $200 more than Mabel.

6 units + 90 ------- 4 units + 80 + 30 + 200
2 units ------- 220
1 unit ------- 110

Mabel @ first -------- (5*110)+ 200 ------750

Best wishes

[tianzhu]

sunnydays2:

3. The ratio of the number of boys to the number of girls in a hall was 3:7. After 64 boys and 64 girls left the hall, the ratio of the number of boys to the number of girls became 2:5. Find the number of pupils in the hall at first.

Hi

Since equal number of boys and girls left the hall, the difference in the number of boys and girls stayed the same.

At first
Boys: Girls ------- 3: 7 (difference ---- 4) -------- 9: 21 (difference ---- 12)

In thye end
Boys: Girls ------- 2 : 5 (difference ---- 3) ------- 8 : 20 (difference ---- 12)

1 unit ------ 64

Number of pupils@first ------- 64*30 -------- 1920

Best wishes