Q&A - P5 Math
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tianzhu:
Dear Tianzhu,pineapple tarts:
Huh? again ah? I think my eyes are beginning to see stars. St.Nick CA1 2010 for P5 Q.18
Hi
Good Morning.
131 is one of possible answers. The others are 107, 119 or 143.
You can do a check with the other numbers and will be able to see that the conditions are met.
http://www.orlesson.org/orp/10Ma/2010-P5-Math-CA1-StNic.pdf
Perhaps, you may want to clarify with the school teacher.
Best wishes
Thank u for your kind effort. Can u advise how to derive at 131, pls? -
pineapple tarts:
Hi
Dear Tianzhu,
Thank u for your kind effort. Can u advise how to derive at 131, pls?
You're welcome.
Usually, primary kids use “SL” to solve such questions.
SL ----- Systematic Listing.
Although it may be tedious, such questions are usually “pao chiak one” like durians so long kids don’t make silly mistakes in their calculations.
Get your kid to use “SL” to get a feel of it. Use it with logical reasoning as it helps to save some time.
There are alternative if kids can see from different perspective.
In this case, a faster approach, if you add 1 to 3 or 1 to 5, the new number can be divided by 4 or 6. In other words, the new number is a multiple of 12.
Multiples of 12 from 100 to 150 are 108,120,132 or 144
Take away 1, the numbers are 107,119,131 or 143
Best wishes -
Pls help !
In May, the average number of particpants in one pottery class was 24. In June, 5 new pottery classes were added. The average number of participants in all the pottery classes became 26. If there were 32 participants in each of the new pottery classes, find the total number of participants in all the pottery classes in June.
Thank you. -
2DMommy:
HiPls help !
In May, the average number of particpants in one pottery class was 24. In June, 5 new pottery classes were added. The average number of participants in all the pottery classes became 26. If there were 32 participants in each of the new pottery classes, find the total number of participants in all the pottery classes in June.
Thank you.
This question has been discussed before.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=68&t=25129&start=1260
32 – 26 ------ 6
6*5 ------ 30
26 – 24 ------- 2
Number of existing classes (May) ------- 30/2 ------ 15
Total number of classes in June ------ 20 (15+5)
Total nos. of participants in all pottery classes in June ------ 26*20 ------ 520
Best wishes -
Please help. Thank you.
Q) Both shops , ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr. Muthu were to buy from shop XYZ, he would have paid $38.25 less than the discounted price in Shop ABC.
a) What was the difference in the original price of the mattress between the two shops?
b) The original price of the mattress in Shop ABC was $1510. What was the minimum percentage discount it must offer so that the discounted price in Shop ABC would be lower than the discounted price in shop XYZ? Give your answer correct to the nearest percent. -
one more please.
Q) There were 1600 pupils in a primary school. when the number of boys increased by 76 and the number of girls decreased by 4%, the total enrolment in the school increased by 3%. How many boys were there in the school at first? -
happyheart:
Hione more please.
Q) There were 1600 pupils in a primary school. when the number of boys increased by 76 and the number of girls decreased by 4%, the total enrolment in the school increased by 3%. How many boys were there in the school at first?
Where is this question from?
It helps to start with a simple diagram.
1.03*1600 ----- 1648
76 – 48 ------ 28
4% of girls ------- 28
100% of girls ------- 700
Number of boys@first ------- 900
Best wishes -
Pls help. Thank u.
The avg # of sit ups performed by 15 girls and some boys was 50.
The avg # of sit UPS performed by the girls was 80% of the avg # of situps performed by all the pupils.
The avg # of situps performed by the boys was 30% more than the avg # of situps performed by the girls.
A) what was the avg #of situps performed by the girls?
B) what% of the pupils were boys? -
zeemimi:
HiPls help. Thank u.
The avg # of sit ups performed by 15 girls and some boys was 50.
The avg # of sit UPS performed by the girls was 80% of the avg # of situps performed by all the pupils.
The avg # of situps performed by the boys was 30% more than the avg # of situps performed by the girls.
A) what was the avg #of situps performed by the girls?
B) what% of the pupils were boys?
Just curious, where is this question from?
avg # of sit ups performed by 15 girls and some boys ------ 50.
avg # of sit UPS performed by the girls -------- 80% of 50 ------- 40
avg # of situps performed by the boys -------- 130% of 40 ------- 52
15*10 -------- 150
52 – 50 -------- 2
Number of boys ------ 150/2 ------- 75
75/90*100% -------- 83.33% (83 1/3)
Best wishes -
happyheart:
HiPlease help. Thank you.
Q) Both shops , ABC and XYZ , offered a 15% discount for the same type of mattress. If Mr. Muthu were to buy from shop XYZ, he would have paid $38.25 less than the discounted price in Shop ABC.
a) What was the difference in the original price of the mattress between the two shops?
b) The original price of the mattress in Shop ABC was $1510. What was the minimum percentage discount it must offer so that the discounted price in Shop ABC would be lower than the discounted price in shop XYZ? Give your answer correct to the nearest percent.
15% ------- 38.25
100% ------- 255 (original price in XYZ)
For ABC ------ 255*100/85 ------- 300
a)Difference -------300 – 255 ------- 45
For (b)
Discounted price in ABC -------- 1510*0.85 ------ 1283.50
Discounted price in XYZ -------- 1283.50 – 38.25 ------- 1245.25
1510 – 1425.25 ------- 264.75
264.75/1510*100% ------- 18%
Best wishes