Q&A - PSLE Math

[tianzhu]

Michaelia0816:

Could anyone kindly help me to solve the question below, thx you.


Sani and Roney had a total of 398 game cards, Sani had 74 more game cards than Roney. After Roney had sold 25% fewer game cards than Sani, he had half as many game cards left as Sani. How many game cards had Roney left?

Hi

You may use MD or UP.

Due to time constraints, I’ll skip the MD.

At first
Roney -------- 162
Sani ------- 236

Sold
Roney -------- 3u
Sani ------- 4u

In the end
Roney -------- 1p
Sani ------- 2p

3u + 1p ------ 162
(x2)
6u + 2p ------- 324

4u + 2p ------- 236

Equalize the parts.

2u ------- 88

1u ------- 44

132 + 1p -------- 162

1p ------- 30(Roney’s cards @end)

Best wishes

[kwcllf]

charsen:

kwcllf:

Hi please help.


2 pieces of ribbon and 3 pieces of lace cost $10.
3 pieces of ribbon and 2 pieces of lace cost $y.
What is the total cost of 1 piece of ribbon and 1 piece of lace?
Give the answer in terms of y.


Thanks!

Hi
This question can be solved using grouping method.

You can find the price of 5 pieces of ribbon and 5 pieces of lace,which is
$(10+y).
So cost of one ribbon and 1lace is
$(10+y)/5=(2+y/5)(ans)
Cheers.

Thanks charsen!

[Dazzle]

Pls help. Q 9 from MGS Prelim 2012


Bottle A and bottle B both contain some juice.
If 1.3 litre of juice was poured into bottle A, the volume of juice in A will be 1.6 times that of the volume of the juice in bottle B.
If 480 ml of juice was poured into bottle B, the volume of juice in bottle B will be 1.8 times that of the volume of the juice in bottle A.

(a) What is the volume of juice in bottle A? (Ans. 1.1 litre)
(b) what is the difference in the volume of juice in both bottles? (Ans: 0.4 litre)

[tianzhu]

rsorchid:

Pls help, Thanks.


A florist had some roses, tulips and carnations. After selling some of them, there were 6 tulips for every 5 roses and 7 roses for every 3 carnations. After selling 168 roses, she had 456 tulips and carnations left. The number of tulips sold was the same as the number of carnations sold.
a) How many roses had she at first?
b) If the number of tulips was twice the number of carnations at first, what is the total number of tulips and carnations sold?

Hi

A neat way is to use MD.

T:R ------ 6:5 -------42:35

R:C ------ 7:3 -------- 35:15

Since the share for roses is repeated, make it the same for both set of ratios

15 + 42 ------ 57

57 units -------- 456

1 unit ------- 8

(a)Number of roses left ------- 35*8 -------- 280

Number of roses@first -------- 280+168 -------- 448

(b) Draw 1 box to show number of tulips/carnation sold.

Number of tulips left ------- 42*8 -------- 336

Number of carnations left -------- 120

1 box + 336 ------- 1 box + 120 = 1 box + 120

1 box ------- 96

The total number of tulips and carnations sold ------- 96*2 ------- 192

Best wishes

[whitety]

Hi, need help on this qn.


Lina bought some chocolate and vanilla muffins in the ratio 2:3. She packed the chocolate muffins into boxes of 3 and the vanilla muffins into boxes of 4. There were 6 more boxes of vanilla muffins than chocolate muffins. How many chocolate muffins did Lina buy?

Thanks!

[jewelbox]

MathIzzzFun, thanks for the explanation on ext angle of triangle. :thankyou:

[tianzhu]

Dazzle:

Pls help. Q 9 from MGS Prelim 2012


Bottle A and bottle B both contain some juice.
If 1.3 litre of juice was poured into bottle A, the volume of juice in A will be 1.6 times that of the volume of the juice in bottle B.
If 480 ml of juice was poured into bottle B, the volume of juice in bottle B will be 1.8 times that of the volume of the juice in bottle A.

(a) What is the volume of juice in bottle A? (Ans. 1.1 litre)
(b) what is the difference in the volume of juice in both bottles? (Ans: 0.4 litre)

Hi

This question touches on the \"double if\" scenarios.

You may use MD or UP.

The steps are rather mechanical, students need to practise to get the hang of it.

Some may use the term \"Cross multiply\" instead of \"Equalising the parts\".They serve the same purpose that is to enable you to make a comparison.

Hope this helps.

Best wishes

http://farm9.staticflickr.com/8042/8011336725_941b3990a6_z.jpg\">

[jewelbox]

Hi, appreciate any help to solve these qns. Thanks.


1)In a sch hall, chairs were arranged in rows such that there were exactly 9 chairs in each row. For a concert, Mr ong brought 6 more chairs into the hall and rearragned all the chairs. Thee are now exactly 7 chairs in each row and 12 more rows than before. How many chairs are there in the sch hall for the concert? (PSLE qn)

2. Chairs are arranged in rows in a sch hall. There are 6 chairs left over if 13 chairs are put in each row. Hwoever, if 15 chairs are arranged in each row, there will be a shortage of 4 chairs. if the no. of people attending the concert is betw 200 and 30, find the no. of chairs in the hall.

3. When K’s age was twice Bala’s age, M’s age was 30. When M’s age was twice K’s age, Bala’s age was 21. Given that M was the olderst among the 3 persons, find B’s age when M was 62 years old. (Ans: 35)

[tianzhu]

whitety:

Hi, need help on this qn.


Lina bought some chocolate and vanilla muffins in the ratio 2:3. She packed the chocolate muffins into boxes of 3 and the vanilla muffins into boxes of 4. There were 6 more boxes of vanilla muffins than chocolate muffins. How many chocolate muffins did Lina buy?

Thanks!

Hi

2:3 ------- 24:36

This is equivalent to 8 boxes of chocolate muffins and 9 boxes of vanilla muffins.

We are looking for 6 more boxes of vanilla muffins.

Hence multiply by 6 to get 48 of chocolate muffins and 54 boxes of vanilla muffins.

Number of chocolate muffins ---------- 48*3 ------ 144

Best wishes

[tianzhu]

jewelbox:

3. When K's age was twice Bala's age, M's age was 30. When M's age was twice K's age, Bala's age was 21. Given that M was the olderst among the 3 persons, find B's age when M was 62 years old. (Ans: 35)

Hi

Please refer to this solution.

Hope this helps.

Best wishes

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