Q&A - PSLE Math

[lymmlim]

Hi,


Need help on the the following problem :

In the 2 classes 6A and 6B, the total number of girls was 100% more than the total number of boys. The ratio of boys to girls in 6A was 3:4 and the ratio of boys to girls in class 6B was 1:6. If there were 8 more girls in class 6A than class 6B, find the number of pupils in class 6A.

Thanks

[tianzhu]

lymmlim:

Hi,


Need help on the the following problem :

In the 2 classes 6A and 6B, the total number of girls was 100% more than the total number of boys. The ratio of boys to girls in 6A was 3:4 and the ratio of boys to girls in class 6B was 1:6. If there were 8 more girls in class 6A than class 6B, find the number of pupils in class 6A.

Thanks

Hi

This question has been discussed in one of the earlier posts.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=27&t=280&start=3140

Best wishes

[youngtay]

Hi, carebear


Thanks

[youngtay]

Hi, MathIzzzFun


Thanks. Sorry for question (2) I still don’t understand, why is it that when 10 red beads are added, blue beads are 3 units however, when 30 blue beads are added, blue beads become six units?

TIA

[MathIzzzFun]

youngtay:

Hi, MathIzzzFun


Thanks. Sorry for question (2) I still don't understand, why is it that when 10 red beads are added, blue beads are 3 units however, when 30 blue beads are added, blue beads become six units?

TIA

Hi youngtay,

Before adding the blue beads, the number of red beads is 2u. After 30 more blue beads are added, 75% of the beads are blue ie 3/4 of the beads are blue. This means that the red beads makes up 1/4 of the beads.

1/4 > 2u
3/4 > 6u

cheers.

[youngtay]

Hi, MathIzzzFun


Thanks

[MathIzzzFun]

youngtay:

Hi, MathIzzzFun


Thanks

Hi

avec plaisir

cheers.

[HoSayLiao]

Can someone help with this question?


Ali has $300. He lost 1/3 of it and ends up with $200. To have the $300 again, he needs to win $100 which is ½ of the $200. 1/3 is known as the Losing Fraction (LF) and ½ is known as the Winning Fraction (WF). ½ times 1/3 = 1/6. 1/6 is the product of the LF and WF, known as the PLW. Find the LF and the WF if the PLW is 81/400.

[Hifive]

Hi


Need help with this question:

A motorist sets off from Town A for Town B.
If he travels at 60km/hr, he will reach Town B at 9.30am.
If he travels at 80km/hr, he will reach Town B at 8.45am
How far apart is Town A and Town B ?

Thanks in advance!

[carebear]

Hifive:

Hi


Need help with this question:

A motorist sets off from Town A for Town B.
If he travels at 60km/hr, he will reach Town B at 9.30am.
If he travels at 80km/hr, he will reach Town B at 8.45am
How far apart is Town A and Town B ?

Thanks in advance!

I only how to solve this question with algebra.

Let x be the distance between A and B.

If the motorist travels at the faster speed, he will take 45 minutes or 3/4h faster to reach B.

Time taken in hours to reach B if he travels at 60km/h is x/60
Time taken in hours to reach B if he travels at 80km/h is x/80

x/60 = x/80 +3/4

x= 180 km

Distance between Town A and Town B is 180 km.