Q&A - PSLE Math

[MathIzzzFun]

tech_nomax:

At Station A, the ratio of the number of children to the number of adults on a train was 4:5. At the next station, 12 children alighted and 10 adults boarded the train. The ratio of the number of children to the number of adults on the train then became 7:10. How many children were on the train at first?

Hi

At first, Children : Adults --> 8u : 10u
In the end, Children : Adults --> 7u + 7 : 10u + 10
So, 8u - 12 = 7u +7
1u --> 19

Children, at first --> 8 x 19 = 152

cheers.

[Neat]

MathIzzzFun:

Neat:

Hi!


Please help to solve the question:

The ratio of the number of males to the number of females at a performance is 5:7. 1/4 of the males and 3/4 of the females are children. What is the ratio of the number of adults to children? Express your answer in simplest form.

Thanks

Hi

ratio of males : females --> 5 : 7 --> 20 : 28
ratio of boys: men --> 5:15 (**1/4 of 20 : 3/4 of 20)
ratio of girls :women --> 21:7 (**3/4 of 28 : 1/4 of 28)
So,
ratio of adults : children --> 22: 26 = 11 : 13

cheers.

Thanks MathIzzzFun

:thankyou:

[small]

Please help and many thanks in advance.


Question:
Vivian has some sweets. If she shares the sweets among 4 friends,5 friends or 9 friends, the remainder is 3,4 or 8 sweets respectively.What is the least possible number of sweets she can have?

[MathIzzzFun]

small:

Please help and many thanks in advance.


Question:
Vivian has some sweets. If she shares the sweets among 4 friends,5 friends or 9 friends, the remainder is 3,4 or 8 sweets respectively.What is the least possible number of sweets she can have?

Hi small,

share with 4,5,9 friends --> total 5,6,10 people
remainder --> 3,4,8
compare the number of people and remainder, you will see that if you were to add 2 to each remainder, the total number will be divisible by 5,6,10 respectively.

So, least possible number of sweets = lowest common multiple of 5,6 & 10 - 2

cheers.

[small]

:thankyou: so much MathIzzzFun.


So the answer is 28 sweets.

[MathIzzzFun]

small:

:thankyou: so much MathIzzzFun.


So the answer is 28 sweets.

good morning, small... that's correct


cheers.

[tech_nomax]

MathIzzzFun:

tech_nomax:

At Station A, the ratio of the number of children to the number of adults on a train was 4:5. At the next station, 12 children alighted and 10 adults boarded the train. The ratio of the number of children to the number of adults on the train then became 7:10. How many children were on the train at first?

Hi

At first, Children : Adults --> 8u : 10u
In the end, Children : Adults --> 7u + 7 : 10u + 10
So, 8u - 12 = 7u +7
1u --> 19

Children, at first --> 8 x 19 = 152

cheers.

:thankyou: very much MathIzzzFun!

could you please let me know in line two, why to write
In the end, Children : Adults --> \"7u + 7 : 10u + 10\", instead of \"7u : 10u\".

Thanks in advance.

[brastilava]

Hi, please assist in this problem (sorry, not sure how to attach image):


The figure shows two quadrants. Find length AB.

http://i47.tinypic.com/xclyyr.jpg

[Nebbermind]

brastilava:

Hi, please assist in this problem (sorry, not sure how to attach image):


The figure shows two quadrants. Find length AB.

http://i47.tinypic.com/xclyyr.jpg

When u extend the smaller quartrant to become a semi-circle overlapping the bigger quartrant, u will see the answer.

[brastilava]

Hi Nebbermind, I see it! Thanks so much:)