Q&A - P5 Math

[chokos]

Hi,

Manage to get the solution for Q4,pls let me know if there is a faster way to do it.

Solution:
----------
If Jason and Keven spent $100 and $50 each day respectively,
Equation 1
------------
J - (100 * number of days) = 1300
K - (50 * number of days) = 0

If Jason and Kevin spent $50 and $100 each day respectively,
Equation 2
------------
K - (100 * number of days * 1/2 )= 0
(inorder to get $0, the days have to be shorter by ½ as he spent twice the amount)
J - (50 * number of days * 1/2 ) = 3700
Therefore,
J – ( 25 * number of days) = 3700

Compare with Equation 1
----------------------------
J - (100 * number of days) = 1300
75 * number of days = 2400
Number of days = 2400 / 75 = 32
J = 1300 + 100 * 32 = $4500

[cimman]

buds:

I am thinking of a fraction.
The sum of its numerator and denominator is 20.
When i add 22 to its denominator, the fraction becomes 1/6.
What is the fraction i am thinking of?

I've recently developed a way to solve problem sums with algebra and simultaneous equations. It offers a simple way of forming the necessary equations. For the above problem, it is an equation with one unknown.
http://i40.tinypic.com/3347uxs.png\">
The fonts in black are values transferred directly from the problem to the table. The fonts in red are calculated values.
The calculation is based on this basic formula: Before + Transfer = After
how did I get (6 units - 22) for Denominator (Before) ?
it is from Before = After - Transfer
= 6 units - (+22)
= 6 units - 22
Since there was no mention of any changes to the Numerator, we put a 0 in the Transfer box for numerator.

The red circle simply circles the relevant equation.
All equations are dervied directly from the table.

If you're open to algebra and simultaneous equations, this method can solve complex problems easily, ie. the equations can be formed easily through the table alone. From the table, the relationships can be clearly seen without a deep comprehension of the problem sum and the relationships of the data values.
The relationships are derived from the table instead of from the problem sum.

[YumYum]

Hi, Can someone pls help with this question:


Farmer Tan has ducks and cows on his farm. The total number of ducks and cows is between 20 and 40. The ratio of the total number of ducks’ legs to the total number of cows’ legs is 5:9. What is the total number of ducks and cows on the farm?

Thanks

[tianzhu]

YumYum:

Hi, Can someone pls help with this question:


Farmer Tan has ducks and cows on his farm. The total number of ducks and cows is between 20 and 40. The ratio of the total number of ducks' legs to the total number of cows' legs is 5:9. What is the total number of ducks and cows on the farm?

Thanks

Hi

One needs to differentiate the ratios representing the number of legs and the number of animals. The ratios for the number of legs and the number of animals are of different measures.

The total number of ducks' legs to the total number of cows' legs is 5:9 ------ 20:36 (equivalent ratios)

A duck ----- 2 legs, a cow ----- 4 legs

This means the total number of ducks to the total number of cows ----- 10:9 -----20:18

Ducks ----- 20
Cows ----- 18

There are 38 ducks and cows.

Best wishes

[ariasnow]

Need help on this question.



Ali’s salary was 5/6 of Teri’s salary. After Ali and Teri each spent $1080, Ali then had 7/9 as much as money as Teri. How much was their combined income?

thanks.

[ariasnow]

Another question:


Sam had 20 more cards than Tony. During a game, Tony lost 14 of his cards to Sam. In the end, Sam had 4 times the number of cards that Tony had. How many cards did Sam have at first?

[tianzhu]

ariasnow:

Need help on this question.



Ali's salary was 5/6 of Teri's salary. After Ali and Teri each spent $1080, Ali then had 7/9 as much as money as Teri. How much was their combined income?

thanks.

Hi

Since Ali and Teri spent the same amount of money(1080), the difference in their salary did not change.

At first

Ali:Teri -----5:6 (Difference – 1) ------ 10:12 ((Difference – 2)

In the end

Ali:Teri -----7:9 (Difference – 2)

Make the difference in units the same.

3 units ------ 1080
1 unit ------ 360

Combined salary ------ 22*360 ------- 7920

Best wishes

[ariasnow]

Another question.


Tom was reading a book. He read 1/8 of it on the first day, 1/5 of it on the 2nd day and 1/4 of it on the 3rd day. After that, he still had 68 pages to read. How many pages does the book have?

[ariasnow]

Pls help with the above questions with thanks.


Another question,

Wendy had $230 and Mary had $38. When their mother gave them each an equal amt of money, Wendy had 4 times as much as Mary. How much did their father give EACH of them?

[ariasnow]

Need help on this. thanks.


Ali, Bala and Charles shared a sum of $. Ali recieved 1/3 of the amt that Bala and Charles recieved altogether. The amt Bala recieved is 1/2 of the total amt that Ali and Charles recieved. If Charles recieved $110, find the total amt that Ali and Bala recieved altogether.