Tutor MathsGuru: Ask me for your burning Maths questions!

[CoffeeCat]

Immasimplegirl:

Need help with this question:


5 friends were playing Wii games on a Friday afternoon from 3pm to 6pm. As there were only 4 consoles, they took turns to play. At any time, 3 of them played while the other 2 friends watched. If each of them had the same amount of playing time, how many minutes did each child play that afternoon?
Thanks:D

This looks so very similar to 1 psle maths question 2 yrs ago.
Hmm this is weird, only 3 people played when there are 4 consoles.
Assuming only 3 played at any instant, it translates to 3*3 = 9 hours of total playing time, shared among the 5 friends equally, which translates to 108minutes playing time per friend.

[she0407]

CoffeeCat:

she0407:

Need help for P5 math problem. :?


1. Mr Heng paid $45 for 7 goldfish and 6 guppies. Each goldfish cost 12 times as much as a guppy. How much more did he pay for a goldfish than a guppy?

2. Mr Lim paid $220 for 5 singlets and 5 jackets. Each jacket cost 10 times as much as a singlet. Find the price of 2 singlets and 3 jackets.

:?:


Thank you!

1)
Cost of 1 goldfish = cost of 12 guppies.
Cost of 7 goldfish = cost of 12*7=84 guppies.
Cost of 7 goldfish and 6 guppies = cost of 90 guppies.
Hence cost of 1 guppy = $0.50.
2)Cost of 1 jacket = cost of 10 singlets.
cost of 5 jackets & 5 singlets = cost of 55 singlets.
......

thank you coffeecat. your explaination is very clear. Can I ask you 1 question? Is it a must to draw a model for PSLE math?

Thanks.

[Jcong]

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 is $490 more than the cost of teddy bears.


a) how much did Mrs Tan spend on the teddy bears?

b) how much did one teddy bear cost?

[jieheng]

Jcong:

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 is $490 more than the cost of teddy bears.


a) how much did Mrs Tan spend on the teddy bears?

b) how much did one teddy bear cost?

Hi ,

Answer is on page 339 .

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=6373&start=3380

[Vanilla Cake]

Grateful thanks to Uncle Dharma, jieheng, MathIzzzFun + others for spending your precious time plus effort in providing worked solutions so that it helps my younger sister in her SMOPS 2011’s preparation.

Here’s one from the APMOPS 2005 Q5 as she will be taking part in APMOPS 2011. No Answer is given. Pls help to provide worked solution and thanks in advance.

Five classes A,B,C,D and E took part in an international chess competition.
Each class sent in 2 participants.
The rules of the competition were:
(a) Participants do not compete with each other for more than 1 game,
(b) Participants from the same class cannot compete with each other.
After a few rounds of competitions, it turned out that all had completed different number of games, except for a participant from class A.
How many games had the 2 participants from class A completed?

[Vanilla Cake]

Another 2 questions from APMOPS - Not sure from which year.


Q1
There were 4 cards labeled with letters M, A, T and H respectively. A single-digit number is written at the back of each card. They are then placed side by side, as shown below, so that a four-digit number is obtained. Peter discovered that regardless of the number written behind the \"A\" card, the difference between the four-digit number and hundred times of the sum of its digits is always 4212.
Find the numbers written behind the cards labeled M, T and H respectively.

Note: Picture showing 4 identical boxes placed side by side with M, A, T and H labeled on each box.

Q2
Given that S=1+11+111+1111+...+ 111...1 (100 of 1's)
find the sum of the digits of S.

Answers given
Q1: M=5, T=1 and H=2
Q2: 415

[jieheng]

Chan09:

Need some help


1) 3/5 are $50. 2/3 of the remainder are $10 and $5 notes and the rest are $2 notes. He had twenty four $2 notes. The number of $10 notes is 1/7 of the number of $5 notes. What is the number of $10 notes he has?
Ans: 4

2) the ratio of the number of Chinese pupils to the number of Malay pupils was 10:7. The ratio of the number of Malay boys to Malay girls was 9:5. What was the rato of the number of Malay girls to the number of chinese pupils in it's simplest form?
Ans: 1:2

Thank you :?

Q1)

[--][--][--][--][--][--][--][--][--][--][--][--][--][--][--] (total 15u)

[--] denotes $50

[--] denotes $10 & $5

[--] denotes $2

the reason for using 15u is because of 3/5 are $50. 2/3 of the remainder are $10 and $5 notes

from the model ,

2u -----> 24 (He had twenty four $2 notes)

1u -----> 12

4u -----> 48

total number of ($10 & $5) notes = 48



Ratio of $10 : $5 = 1 : 7

the number of $10 notes is 1/8 of the total number of ($10 & $5) notes = (1/8) * 48 = 6 (Ans)


Q2)


Malay boys 9u

Malay girls 5u

total Malay pupils = 9u + 5u = 14u


Chinese pupils 10u

Malay pupils 7u

Need to change the Malay pupils from 7u -----> 14u for easy comparison

Chinese pupils 10u*2 -----> 20u

Malay pupils 7u*2 -----> 14u


the rato of the number of Malay girls to the number of chinese pupils in it's simplest form = 5u : 20u = 1 : 4 (Ans)

[jieheng]

Vanilla Cake:

Another 2 questions from APMOPS - Not sure from which year.


Q1
There were 4 cards labeled with letters M, A, T and H respectively. A single-digit number is written at the back of each card. They are then placed side by side, as shown below, so that a four-digit number is obtained. Peter discovered that regardless of the number written behind the \"A\" card, the difference between the four-digit number and hundred times of the sum of its digits is always 4212.
Find the numbers written behind the cards labeled M, T and H respectively.

Note: Picture showing 4 identical boxes placed side by side with M, A, T and H labeled on each box.


Answers given
Q1: M=5, T=1 and H=2

M*1000+A*100+T*10+H - 100*(M+A+T+H) = 4212

M*1000+T*10+H - 100*(M+T+H) = 4212

=> H = 2 , T = 1

M*1000+10+2 - 100*(M+1+2) = 4212

M*1000-M*100 = 4500

=> M = 5

[Vanilla Cake]

Pls help to provide worked solutions and thanks in advance.

Answer given: m=1

http://postimage.org/image/2uvidl31g/

[Vanilla Cake]

Pls help to provide worked solutions and thanks in advance.

No answer given

http://postimage.org/image/2uwahpzfo/