Q&A - PSLE Math

[ozora]

MathIzzzFun:

ozora:

need quick help:

Some plates and cups were packed into blue and red boxes.There were 12 more blue boxes than red boxes.Each blue box contained 120 plates and each red box contained 150 plates.Given that there were 120 fewer plates than cups in total,how many plates were there?
Thanks in advance

Hi

this is a variation of the typical \"counting coins\" problem sum.

There are 120 more cups than plates...& 12 more blue boxes (cups) than red boxes (plates)

each blue box has 30 less cups than plates in red box.

make the number of boxes the same - either add red boxes, or remove blue boxes. Since we are looking for number of plates (red boxes), we remove blue boxes.

remove 12 blue boxes so that there are now equal number of boxes.
12 x 120 cups = 1440 cups, there are now 1440 - 120 = 1320 lesser cups than plates in the boxes.

each blue box has 30 less cups than plates in red boxes, 1320 / 30 = 44
there are 44 red boxes and 44+12 = 56 blue boxes

number of plates = 44 x 150 = 6600

cheers.

thanks.. may i know how to get\" each blue box has 30 less cups than plates in red box.\"


it looked so easy to you but really tough on me and the kids to comprehend.

[MathIzzzFun]

ozora:

MathIzzzFun:

[quote=\"ozora\"]need quick help:

Some plates and cups were packed into blue and red boxes.There were 12 more blue boxes than red boxes.Each blue box contained 120 plates and each red box contained 150 plates.Given that there were 120 fewer plates than cups in total,how many plates were there?
Thanks in advance

Hi

this is a variation of the typical \"counting coins\" problem sum.

There are 120 more cups than plates...& 12 more blue boxes (cups) than red boxes (plates)

each blue box has 30 less cups than plates in red box.

make the number of boxes the same - either add red boxes, or remove blue boxes. Since we are looking for number of plates (red boxes), we remove blue boxes.

remove 12 blue boxes so that there are now equal number of boxes.
12 x 120 cups = 1440 cups, there are now 1440 - 120 = 1320 lesser cups than plates in the boxes.

each blue box has 30 less cups than plates in red boxes, 1320 / 30 = 44
there are 44 red boxes and 44+12 = 56 blue boxes

number of plates = 44 x 150 = 6600

cheers.

thanks.. may i know how to get\" each blue box has 30 less cups than plates in red box.\"


it looked so easy to you but really tough on me and the kids to comprehend.[/quote]Hi

..I read the question as \"Each blue box contained 120 cups and each red box contained 150 plates.\", otherwise, it is not possible to solve because there is no mention of number of cups any where.

cheers.

[pensiveowl]

Pls help us ans this problem, thanks:


In the elections committee, 40% of the members were men and the rest were women. When 210 members resigned from the club, the number
of men became 1/4 of the original number of men and the number of women decreased by 20%.
(a) How many women were in the club at first ?
(b) How many men resigned from the club ?

[wanderlust-alm]

After resignation of members , % of man is 10% ( of the original number ) as 1/4 of 40% is 10%.

After reignation of members, % of woman is 48% ( of original number ) as 80% x 60% ( original % ) is 48%.
hence members who quit is 100-10-48 = 42% ==> 210 members.

Number of woman in the club at first = 60% x 210 / 42 = 300 women
Number of men resigned from club = 30% x 210 / 42 = 150 men.

[pensiveowl]

Nice! - thanks!

wanderlust-alm:

After resignation of members , % of man is 10% ( of the original number ) as 1/4 of 40% is 10%.
After reignation of members, % of woman is 48% ( of original number ) as 80% x 60% ( original % ) is 48%.
hence members who quit is 100-10-48 = 42% ==> 210 members.

Number of woman in the club at first = 60% x 210 / 42 = 300 women
Number of men resigned from club = 30% x 210 / 42 = 150 men.

[raghupavithra]

round off 378.71 to the nearest whole number


1. 376
2. 378
3. 379
4. 380

pls help

[CloudeeDaz]

Hi

need help withthis question

Mdm Zhang packed some beads into 14 small boxes and 15 big boxes. There were equal no of beads in each small box and equal no of beads in each big box. Each big box contained 5 more beads than each small box. 3/8 of the beads were packed in small boxes. How many beads were there in each small box?

thanks

[MathIzzzFun]

CloudeeDaz:

Hi

need help withthis question

Mdm Zhang packed some beads into 14 small boxes and 15 big boxes. There were equal no of beads in each small box and equal no of beads in each big box. Each big box contained 5 more beads than each small box. 3/8 of the beads were packed in small boxes. How many beads were there in each small box?

thanks

Hi

this was discussed in an earlier post..

http://www.flickr.com/photos/62167097@N02/5664739745/in/photostream

cheers.

[CloudeeDaz]

thanks for the link!

[wanderlust-alm]

CloudeeDaz:

Hi

need help withthis question

Mdm Zhang packed some beads into 14 small boxes and 15 big boxes. There were equal no of beads in each small box and equal no of beads in each big box. Each big box contained 5 more beads than each small box. 3/8 of the beads were packed in small boxes. How many beads were there in each small box?

thanks

Each big box has 5 more beads ==> extra beads over the small box ==> 75 beads.

14 small box + 15 small box + 75 beads = total amount of beads ( Y beads )

each small box contain ( 3/8 y ) / 14 beads ==> 3/112 y
Beads in big box = 3/8 y + 3/112 y + 75 beads

hence total number of beads = 3/8 y + ( 3/8 y + 3/112 y + 75 )

Work out to common denominator

42/112 + 42/112 + 3/112 + 75 beads = total number of beads

87/112 + 75 beads = total number of beads

==> 25 /112 = 75 beads
hence 3 / 8 = 126 beads

hence each small box has 126/14 = 9 beads