Q&A - P5 Math

[MathIzzzFun]

S-H:

Hi, pls kindly help me to solve these 2 questions :-



2) A school had 1/3 of its pupils wearing glasses in January. By the end of the year 160 pupils wearing glasses left the school. The fraction of pupils wearing glasses at the end of the year became 1/4.
(a) How many pupils were wearing glasses in January?
(b) How many pupils were there in the school at the end of the year?

Thank you very much.

Number of pupils not wearing glasses in Jan = 2/3
Number of pupils not wearing glasses at end of year = 3/4

2/3 of pupils in Jan = 3/4 of pupils at end of year
6/9 of pupils in Jan = 6/8 of pupils at end of year

Pupils in Jan --> 9 units
Pupils at end of year --> 8 units
1 unit left the school --> 160

Number of pupils wearing glasses in Jan --> 3 units = 480
Number of pupils in school at end of year --> 8 units = 1280

cheers.

[S-H]

MathIzzzFun:

S-H:

Hi, pls kindly help me to solve these 2 questions :-



2) A school had 1/3 of its pupils wearing glasses in January. By the end of the year 160 pupils wearing glasses left the school. The fraction of pupils wearing glasses at the end of the year became 1/4.
(a) How many pupils were wearing glasses in January?
(b) How many pupils were there in the school at the end of the year?

Thank you very much.

Number of pupils not wearing glasses in Jan = 2/3
Number of pupils not wearing glasses at end of year = 3/4

2/3 of pupils in Jan = 3/4 of pupils at end of year
6/9 of pupils in Jan = 6/8 of pupils at end of year

Pupils in Jan --> 9 units
Pupils at end of year --> 8 units
1 unit left the school --> 160

Number of pupils wearing glasses in Jan --> 3 units = 480
Number of pupils in school at end of year --> 8 units = 1280

cheers.

Thank you! What about qtn 1? Thanks

[MathIzzzFun]

S-H:

MathIzzzFun:

[quote=\"S-H\"]Hi, pls kindly help me to solve these 2 questions :-



2) A school had 1/3 of its pupils wearing glasses in January. By the end of the year 160 pupils wearing glasses left the school. The fraction of pupils wearing glasses at the end of the year became 1/4.
(a) How many pupils were wearing glasses in January?
(b) How many pupils were there in the school at the end of the year?

Thank you very much.

Number of pupils not wearing glasses in Jan = 2/3
Number of pupils not wearing glasses at end of year = 3/4

2/3 of pupils in Jan = 3/4 of pupils at end of year
6/9 of pupils in Jan = 6/8 of pupils at end of year

Pupils in Jan --> 9 units
Pupils at end of year --> 8 units
1 unit left the school --> 160

Number of pupils wearing glasses in Jan --> 3 units = 480
Number of pupils in school at end of year --> 8 units = 1280

cheers.

Thank you! What about qtn 1? Thanks[/quote]http://i45.tinypic.com/29bc8zp.png\">

cheers.

[jas3angels]

Hi,


Please help to solve this.

There were some marbles in a box. Jenny took out 2/5 of the marbles and an additional 6 more. Then William took out 1/6 of the remaining marbles and an additional 5 more. There were 25 marbles left in the box. How many marbles were in the box at first? :thankyou:

[chloecube]

quekcc:

chloecube:

when Trish gives 10 sweets to Jane, she will have four times as many sweet as Jane. when she gave 20 sweet to Jane, she will have thrices as many sweets as Jane. how many sweet do they have altogether?

http://i49.tinypic.com/zm0ha8.jpg\">

thks for the model!
i understand now

[chloecube]

speedmaths.com:

chloecube:

there were 4 times as many red pens as blue pens in a box. 415 red pens and 45 blue pens were removed from the box. as a result, the number of blue pens became 3 times as many as red pens. how many blue pens were there in the beginning?

Hi,

You may wish to look at the numbers again.

May we know the source of this question?

Cheers


speedmaths.com


.

sorry, typo error.
shld be
there were 4 times as many red pens as blue pens in a box. 415 red pens and 46 blue pens were removed from the box. as a result, the number of blue pens became 3 times as many as red pens. how many blue pens were there in the beginning?

[jieheng]

chloecube:

there were 4 times as many red pens as blue pens in a box. 415 red pens and 46 blue pens were removed from the box. as a result, the number of blue pens became 3 times as many as red pens. how many blue pens were there in the beginning?

R [---------][---------][---------][---------]

B [---------]

R [][][][46][][][][46][][][][46][][][][46]

B [][][][46]

[][][46][][][][46][][][][46][][][][46] --> 415

11u + 46*4 --> 415
11u --> 231
1u --> 21

No of blue pens were there in the beginning = 3u + 46 = 3*21 + 46 = 109 (Ans)

[chloecube]

jieheng:

chloecube:

there were 4 times as many red pens as blue pens in a box. 415 red pens and 46 blue pens were removed from the box. as a result, the number of blue pens became 3 times as many as red pens. how many blue pens were there in the beginning?

R [---------][---------][---------][---------]

B [---------]

R [][][][46][][][][46][][][][46][][][][46]

B [][][][46]

[][][46][][][][46][][][][46][][][][46] --> 415

11u + 46*4 --> 415
11u --> 231
1u --> 21

No of blue pens were there in the beginning = 3u + 46 = 3*21 + 46 = 109 (Ans)

thank you so much !!!

so all for the typo earlier :oops:

[BigDevil]

There are 45 peach tarts, 120 strawberry tarts and 150 chocolate tarts. If all the tarts are placed into the least number of boxes such that there are equal number of each type of tarts in each box, how many tarts are there in each box ?

[MathIzzzFun]

BigDevil:

There are 45 peach tarts, 120 strawberry tarts and 150 chocolate tarts. If all the tarts are placed into the least number of boxes such that there are equal number of each type of tarts in each box, how many tarts are there in each box ?

this question is not structured properly... it would be more logical to replace \"least\" with \"maximum\".

cheers.