Q&A - P5 Math
-
speedmaths.com:
:thankyou:
Hi,Jamesbond:
Lim distributed 300 souvenirs from the art museum to some girls in P4 and P5.
Each P4 girl received 5 souvenirs and each P5 girl received 3 souvenirs. The P4 girls received 60 more souvenirs than those in P5.
How many more P5 girls were there?
Lim distributed 300 souvenirs,
The P4 girls received 60 more souvenirs than those in P5
P5 girls received (300 - 60) / 2 = 120 souvenirs,
P4 girls received (300 + 60) / 2 = 180 souvenirs,
Each P5 girl received 3 souvenirs,
There were 120 / 3 = 40 P5 girls
Each P4 girl received 5 souvenirs,
There were 180 / 5 = 36 P4 girls
40 - 36 = 4 (more P5 girls)
Hope this helps.
speedmaths.com
. -
![](\"http://i46.tinypic.com/1z3wcr8.jpg\")
http://i46.tinypic.com/1z3wcr8.jpg\">
Pl help... -
Jamesbond:
Area of triangle ABF = 1/2 of Area of Rectangle ABEG
Pl help...
Area of triangle BDE = 1/2 of Area of Square BCDE
Hence, Area of the shaded = 1/2 of Area of the whole figure ACDG
= 1/2 * 50 * 16
Cheers. -
Hi, I have 3 qns:
1) At first, there were 234 more apples in Stall A than Stall B. After 78 apples were transferred fr Stall B to Stall A and 24 apples were thrown away fr Stall A, there were 4 times as many apples in Stall A as Stall B. How many apples were there in Stall B at first?
2) 6 pens cost as much as 2 notebooks. 7 pens cost $4.40 more than 1 note book.Danny spent $88 on an equal number of pens and notebooks. How many pens did he buy?
3) A class library had a total of 340 novels , fiction books and comics. After 3/7 of the novels and 25 comics were loaned out, and 30 fiction books were bought, the number of the three types of books were the same. How many comics did the class library have at first?
Tjank you. -
1) At first, there were 234 more apples in Stall A than Stall B. After 78 apples were transferred fr Stall B to Stall A and 24 apples were thrown away fr Stall A, there were 4 times as many apples in Stall A as Stall B. How many apples were there in Stall B at first?
In the end :
A:uuuu
B:u
At first :
A:4u-78+24 (before B give A 78 and also before A throw 24)
B:u+78 (before giving 78 to A)
At first A is 234 more than B ie. A-B=243 so
4u-78+24-u-78=243
3u=234+78-24+78=366
u=122
at first b=122+78 = 200
check
at first A have 434
B give A 78 ; B left 122, A become 512 ; then A throw 24 left 488
488 is 4 times of 122 - correct -
2) 6 pens cost as much as 2 notebooks. 7 pens cost $4.40 more than 1 note book.Danny spent $88 on an equal number of pens and notebooks. How many pens did he buy?
6p=2n or 2n=6p so
n=3p
p:u
n:3u
7p (7u) is $4.40 more than n(3u)
7u-3u=$4.40
4u=$4.40
u=$1.10
p=$1.10 ; n=$3.30
1p+1n=$4.40
$88/$4.40 = 20
Answer : 20p and 20n -
Hi Tianzhu,
Sorry , probably that the below questions has been provided working in the thread but I cannot find. This is one of your questions of the two changed quantities. I am stuck at the end ratio.
Female male
before 3 : 1
changed 175 -5
after ? ?
13)In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
Thank you -
3) A class library had a total of 340 novels , fiction books and comics. After 3/7 of the novels and 25 comics were loaned out, and 30 fiction books were bought, the number of the three types of books were the same. How many comics did the class library have at first?
n+f+c = 340
n=uuuuuuu (7u)
3/7 n loan out ; n remain 4u
c loan out 25 : c-25; since the number of boos is the same so
c-25=4u
c=4u+25
f+30 (bought 30) = 4u
f=4u - 30
n+f+c = 340
7u + (4u-30) + (4u+25) = 340
15u = 345
u=23
c=4u+25 = 117
check
n=7u = 161
f=4u-30 = 62
117+161+62 = 340 correct -
Musicstar:
Hi Tianzhu,
Sorry , probably that the below questions has been provided working in the thread but I cannot find. This is one of your questions of the two changed quantities. I am stuck at the end ratio.
Female male
before 3 : 1
changed 175 -5
after ? ?
13)In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
Thank you
Hi Musicstar,
Not sure whether can use this method:
After: Female to male = 7u to 3u
Before: Female to male = (7u + 75) to (3u +5) = 75% to 25% = 3 to 1
Therefore: (7u + 75) to (3u +5) = 3 to 1
Which means 7u + 75 = 9u + 15
Hence: 2u = 60. 1u = 30
Answer:
7u + 75 + 3u + 5
= 10u + 80
= 380
Is it accepted? =)) -
13)In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?
before
3u : 1u
change
-75 : -5
after
7p : 3p
then
3u-75ā¦7p
u-5ā¦3p
make the part the same
9u-225=7u-35
2u=190
u=95
at first have 4u = 380
check
at first
285:95
change
-75:5
end
210:90 which is 7:3 - correct
wow learn this today from tianzhu blog!! thanks tianzhu!
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