Q&A - P5 Math

[Essential]

Thank U Mathizzfun…

[Superbugs]

Tao Nan P2 Q15.


Ali has some 50-cent coins and Martin has some $1 coins. Ali has 49 more coins than Martin but has $4.50 less than him. How much money do they have altogether?

My DD used Trial & Error Mtd to obtain the answer of $111.50. Anyone can help with the model Mtd?

[MathIzzzFun]

Superbugs:

Tao Nan P2 Q15.


Ali has some 50-cent coins and Martin has some $1 coins. Ali has 49 more coins than Martin but has $4.50 less than him. How much money do they have altogether?

My DD used Trial & Error Mtd to obtain the answer of $111.50. Anyone can help with the model Mtd?

Hi

If they had same number of coins, then one can easily find the number of coins by dividing the \"total extra amount\" by the \"difference per coin\".

Suppose that they both had same number of coins ie add 49 more coins to Martin - this also means to add $49 more to the difference ie Martin would now have $49 + $4.50 = $53.50 more than Ali.

Since each $1 coin is $0.50 more than a $0.50 coin, the number of coins
that each has = $53.50 / $ 0.50 = 107

So the total amount = 107 x ($1+$0.50) - $49 (since we added 49 $1 coins)
= $ 111.50

cheers.

[MathIzzzFun]

Essential:

Thank U Mathizzfun..

u r welcome

cheers.

[Superbugs]

Tks a lot! This is also much easier to understand!

MathIzzzFun:

Superbugs:

Tao Nan P2 Q15.

Ali has some 50-cent coins and Martin has some $1 coins. Ali has 49 more coins than Martin but has $4.50 less than him. How much money do they have altogether?

My DD used Trial & Error Mtd to obtain the answer of $111.50. Anyone can help with the model Mtd?

Hi

If they had same number of coins, then one can easily find the number of coins by dividing the \"total extra amount\" by the \"difference per coin\".

Suppose that they both had same number of coins ie add 49 more coins to Martin - this also means to add $49 more to the difference ie Martin would now have $49 + $4.50 = $53.50 more than Ali.

Since each $1 coin is $0.50 more than a $0.50 coin, the number of coins
that each has = $53.50 / $ 0.50 = 107

So the total amount = 107 x ($1+$0.50) - $49 (since we added 49 $1 coins)
= $ 111.50

cheers.

[MathIzzzFun]

Superbugs:

Tks a lot! This is also much easier to understand!

MathIzzzFun:

[quote=\"Superbugs\"]Tao Nan P2 Q15.

Ali has some 50-cent coins and Martin has some $1 coins. Ali has 49 more coins than Martin but has $4.50 less than him. How much money do they have altogether?

My DD used Trial & Error Mtd to obtain the answer of $111.50. Anyone can help with the model Mtd?

Hi

If they had same number of coins, then one can easily find the number of coins by dividing the \"total extra amount\" by the \"difference per coin\".

Suppose that they both had same number of coins ie add 49 more coins to Martin - this also means to add $49 more to the difference ie Martin would now have $49 + $4.50 = $53.50 more than Ali.

Since each $1 coin is $0.50 more than a $0.50 coin, the number of coins
that each has = $53.50 / $ 0.50 = 107

So the total amount = 107 x ($1+$0.50) - $49 (since we added 49 $1 coins)
= $ 111.50

cheers.

[/quote]avec plaisir

cheers.

[Chan09]

Dear all,

Need some help on these:
1) Amy was given half a cake and Ben was given 1/3 of the other half. The remaining cake was shared equally among 8 pupils. What fraction of the whole cake did each of the 8 pupils get?
2) if 22 seashells were added to 1/4 of Linda seashells, she would have three times it’s original number of seashells. How many seashells did she have at first?
3) in a test, David was in the 31st position. His position in class was just behind 5/9 of the pupils. How many pupils sat for the test?

Thank you.

[MathIzzzFun]

Chan09:

Dear all,

Need some help on these:
1) Amy was given half a cake and Ben was given 1/3 of the other half. The remaining cake was shared equally among 8 pupils. What fraction of the whole cake did each of the 8 pupils get?
2) if 22 seashells were added to 1/4 of Linda seashells, she would have three times it's original number of seashells. How many seashells did she have at first?
3) in a test, David was in the 31st position. His position in class was just behind 5/9 of the pupils. How many pupils sat for the test?

Thank you.

Hi
1)
Amy = 1/2 cake, Ben = 1/3 x 1/2 cake = 1/6 cake.
Remainder = 1-1/2-1/6 = 1/3 cake.
So each of the 8 pupils get 1/3 divide by 8= 1/24 cake

2)
at first, Linda seashells = 4 units.
1/4 seashells + 22 seashells = 12 units
1 unit + 22 seashells = 12 units
11 units = 22 seashells, 1 unit = 2 seashells.
at first, Linda had 4 x 2 = 8 seashells

3)

30 pupils ahead of David. so, 30 pupils = 5/9 of pupils
Total number of pupils who sat for the test= 9/5 x 30 = 54

cheers.

[ksmama]

Hi, take a look at this q pls

Average mass of 40 kids in class 43.625kg. Av mass of boys 45.5kg. Av mass of girls 42.5kg. After 4 boys left the class, av mass of boys 45kg.
a) fd no. of boys and girls in class at lst
b) when a girl joined the class, av mass of the girls bcam 43.4kg. What was mass of new girl?
Tks

[YumYum]

AiTong SA2, Qn 17 (Paper 2)


Hi, I need help with the foll Qn:

A seamstress had some white and black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first? (Ans : 72)

thanks