Q&A - P4 Math

[MathIzzzFun]

babies:

Hi, need to double check.:)


Q)
Tin jin saved $3500 in April. His monthly salary is twice the amount he saved in April.
He saved $4200 less than the amount he spent in May. How much ddi he save in May?

Is $2800 (saved in May) correct?

Hi

spent $5600 & saved $1400 in May.

Salary --> $3500x 2 = $ 7000
In May,
saved --> 1 unit
spent --> 1 unit + $4200
2 units + $4200 = $7000
1 unit --> $1400, spending in May --> $5600

cheers.

[babies]

MathIzzzFun:

babies:

Hi, need to double check.:)


Q)
Tin jin saved $3500 in April. His monthly salary is twice the amount he saved in April.
He saved $4200 less than the amount he spent in May. How much ddi he save in May?

Is $2800 (saved in May) correct?

Hi

spent $5600 & saved $1400 in May.

Salary --> $3500x 2 = $ 7000
In May,
saved --> 1 unit
spent --> 1 unit + $4200
2 units + $4200 = $7000
1 unit --> $1400, spending in May --> $5600

cheers.

Hi MathIzzzFun,

Well noted & thank you! :rahrah:

[Superbugs]

Steve bought some 20cent and 50cent stamps for $32. The number of 20cent stamps he bought was 1/1/2 times the number of 50cent stamps. How many 20cent stamps did he buy?


Let x be no of 20cents coins and y be no of 50cents coins
Equation 1:
0.20x + 0.50y = 32
2x+5y=320

Equation 2:x=1/1/2y
2(3/2y)+5y=320
8y=320
y=40
Therefore x=60
My kid can understand this after I have done through but this is algebra which he will not learn till P6.
Any other method to solve this question fast and easy to understand?
We tried model method but cannot get the answers. Pls help. Tks

[MathIzzzFun]

Superbugs:

Steve bought some 20cent and 50cent stamps for $32. The number of 20cent stamps he bought was 1/1/2 times the number of 50cent stamps. How many 20cent stamps did he buy?


Let x be no of 20cents coins and y be no of 50cents coins
Equation 1:
0.20x + 0.50y = 32
2x+5y=320

Equation 2:x=1/1/2y
2(3/2y)+5y=320
8y=320
y=40
Therefore x=60
My kid can understand this after I have done through but this is algebra which he will not learn till P6.
Any other method to solve this question fast and easy to understand?
We tried model method but cannot get the answers. Pls help. Tks

Hi

20 cents stamps is 1 1/2 times 50 cents stamps, for 3 20-cents stamps for every 2 50-cents stamps.

Consider 1 packet of 3 x 20-cents stamps + 2 x 50-cents stamps.
Amount paid for this packet = $ 0.60 + $1.00 = $1.60

So, how many packets can you buy with $32 ? -- > $ 32 / $ 1.60 = 20 packets

Number of 20-cents stamps bought --> Number of packets x number of 20-cents stamps in 1 packet = 20 x 3 = 60
Number of 50-cents stamps bought --> Number of packets x number of 50-cents stamps in 1 packet = 20 x 2 = 40

cheers.

[trytry]

Please help to clarify this type of question.

Alice bought 2 similar cakes. She ate 1/3 of a cake. What fraction of the cakes was left?

Will the answer be the same if the question is "What fraction of a cake was left?"

TIA.

[chloecube]

HI,


i have 3 questions that i need help on.

¼ of Hito’s marbles is equal to 1/5 of Troy’s marbles. If they have 36 marbles altogether, how many marbles does Troy have?
Ans 20 but i need the working to explain to DS

Troy baked some cakes to sell at a fair. He sold 80 cakes in the morning and 2/5 of the remaining in the afternoon. The number of cakes not sold was equal to 1/5 of the cakes he baked. How many cales did Troy bake?

There are 80 pupils in Class A and Class B. 4/9 of pupils in Class A are boys and 3/5 of the pupils Class B are girls.
a)\tHow many pupils are there in Class A?
b)\tHow many boys are there in both classes?

[BigDevil]

chloecube:

HI,


i have 3 questions that i need help on.

¼ of Hito’s marbles is equal to 1/5 of Troy’s marbles. If they have 36 marbles altogether, how many marbles does Troy have?
Ans 20 but i need the working to explain to DS

http://i44.tinypic.com/33d8r2w.jpg\">

[chloecube]

BigDevil:

chloecube:

HI,


i have 3 questions that i need help on.

¼ of Hito’s marbles is equal to 1/5 of Troy’s marbles. If they have 36 marbles altogether, how many marbles does Troy have?
Ans 20 but i need the working to explain to DS

http://i44.tinypic.com/33d8r2w.jpg\">

thank you BigDevil

[MathIzzzFun]

chloecube:

HI,


i have 3 questions that i need help on.

¼ of Hito’s marbles is equal to 1/5 of Troy’s marbles. If they have 36 marbles altogether, how many marbles does Troy have?
Ans 20 but i need the working to explain to DS

Troy baked some cakes to sell at a fair. He sold 80 cakes in the morning and 2/5 of the remaining in the afternoon. The number of cakes not sold was equal to 1/5 of the cakes he baked. How many cales did Troy bake?

There are 80 pupils in Class A and Class B. 4/9 of pupils in Class A are boys and 3/5 of the pupils Class B are girls.
a)\tHow many pupils are there in Class A?
b)\tHow many boys are there in both classes?

Hi

Q2...

http://i39.tinypic.com/sb262t.jpg\">

cheers.

[MathIzzzFun]

chloecube:

HI,


i have 3 questions that i need help on.

¼ of Hito’s marbles is equal to 1/5 of Troy’s marbles. If they have 36 marbles altogether, how many marbles does Troy have?
Ans 20 but i need the working to explain to DS

Troy baked some cakes to sell at a fair. He sold 80 cakes in the morning and 2/5 of the remaining in the afternoon. The number of cakes not sold was equal to 1/5 of the cakes he baked. How many cales did Troy bake?

There are 80 pupils in Class A and Class B. 4/9 of pupils in Class A are boys and 3/5 of the pupils Class B are girls.
a)\tHow many pupils are there in Class A?
b)\tHow many boys are there in both classes?

Hi

Q3 is interesting - may I know the source of this question.

Total number of pupils in Class A and Class B --> 80

Number of pupils in Class A is a multiple of 9 and number of pupils of Class B is a multiple of 5. Since the total number 80 is a multiple of 5, then the number of pupils in Class A must also be a multiple of 5.

This means that the number of pupils in Class A is a multiple of 5 & 9 --> 45, 90, 135...so, there are 45 pupils in Class A

Number of pupils in Class B --> 80 - 45 = 35... with this, (b) can be worked out.

cheers.