Q&A - P5 Math

[speedmaths.com]

Hi, need help to solve this question.

Guoming has 120 fish. 3/8 of the fish are goldfish. 1/5 of them are angelfish and the rest are guppies. What fraction of the fish are guppies?

The answer in the book is 17/40.. but i couldn't get it.

thank you in advance.

Hi tracywham,

Let's try:

One possible method:

Guoming has 120 fishes.

(3/8 of the fish are goldfish)
3/8 x 120 = 45 of the fish are goldfish.

(1/5 of them are angelfish)
1/5 x 120 = 24 of them are angelfish

(the rest are guppies)
guppies → 120 - 45 - 24 = 51


(What fraction of the fish are guppies?)

guppies/total → 51/120 → 17/40

Hope this helps

Cheers



speedmaths
.

[geniuskids]

Can anyone help with solving this question using the Branching Method?

[littleprince]

Hi parents, pls help!

there are 90 more boys than girls at a school funfair. after 80% of the boys and 30% of the girls left the funfair. there were twice as many girls as boys that remained. how many boys were at funfair at first?l

Is the answer 120 boys at first?

[littleprince]

[geniuskids]

I have the solution to the following question using the branching method but can someone please tell me how do we know how many to multiply the units by (eg. why x2 in the image). I can't figure it out

[geniuskids]

This is because 2/7 of the salary left= 3/8 of the remainder (i.e. 3u, as shown in the branching).

In order to find what is 1/7 of the salary, the unit must be divisible by 2, hence multiplying by 2 for all the units in the remainder.

So now, 2/7 of the salary= 6u, 1/7 of the salary= 3u and 7/7 of the salary= 3 x 7 = 21u

Personally, I usually don't recommend my students to use branching method as 1. It is tedious to put all the numbers, 2. Sometimes they may put the number wrongly, especially when they are confused with so many numbers and fractions, 3. Don't know what to do thereafter. I will prefer model or ratio method, which illustrates the numbers and units in the question in a much more understandable manner.

Thank you ... It is indeed confusing.

[geniuskids]

I tried using the same method to answer this question but the answer doesn't seem correct. Unfortunately, as the lesson is on branching method practises, I have to do it this way.

[geniuskids]

[belnanna]

Hi.
Can anyone tell me the formular/rule of this question?



Thks in advance!

(n+1)^2 + n

(n+1)^2 + n -- sorry dont understand...

[nansk]

Hi.
Can anyone tell me the formular/rule of this question?

Thks in advance!

(n+1)^2 + n

(n+1)^2 + n -- sorry dont understand...

Fig. Number => Number of Dots
-------------- -------------------------------
1 => (1+1) X (1+1) + 1 = 5
2 => (2+1) X (2+1) + 2 = 11
3 => (3+1) X (3+1) + 3 = 19
n => (n+1) X (n+1) + n = (n+1)^2 + n