Q&A - PSLE Math

[tianzhu]

mn:

Hi, I need help on this question. I manage to get a). Pls help. Thank you.

Machine A and B each printed a fix number of newspapers per hour. Machine B started printing earlier at a rate of 75 copies per hour. After Machine B had printed for 10 hours, Machine A had printed 340 copies. After Machine B had printed for 16 hours, Machine A had printed 886 copies.
a) How many copies of newspapers did Machine A print per hour?
b) How long would Machine B have worked when both machines have printed a total of 2750copies?

Hi

From (a),Number of copies printed by A ----- 91

Number of copies printed by A and B----- 91+75 ------166

Number of copies printed by A and B in 16h ----- 886 + (75*16) ------ 2086

2750 – 2086 ------ 664

664/166 ------- 4

Number of hours by B ------- 16 + 4 ------ 20

Best wishes

[niza6666.028774hotmail.028774com]

Tianzhu, thank you so much for the fast response.

[Spongy]

Hi I need help in this question. Please help. Thanks in advance.


1. At a concert, tickets were sold at $12, $30 and $50. The sales of $12 tickets made up 25% of the total amount of money collected. The sales of $30 tickets made up 60% of the total amount. Given that 5 more $12 tickets were sold than the $30 tickets. how many $50 tickets were sold?

[2632parent]

Hi, can someone help me in this question ? :siao:


1) A shopkeeper had some markers in red and blue. If 50 red markers and 25 blue markers were sold each week, there would be 500 red markers left when all the blue markers were sold. If 25 red markers and 50 blue markers were sold each week, there would be 800 red markers left when all the blue markers were sold. How many markers did the shopkeeper have at first?



:thankyou:

[MathIzzzFun]

Spongy:

Hi I need help in this question. Please help. Thanks in advance.


1. At a concert, tickets were sold at $12, $30 and $50. The sales of $12 tickets made up 25% of the total amount of money collected. The sales of $30 tickets made up 60% of the total amount. Given that 5 more $12 tickets were sold than the $30 tickets. how many $50 tickets were sold?

Hi

total amount of money collected --> $ 60 units
amount from $12 tickets --> $ 15 units
amount collected from $30 tickets --> $ 36 units
amount collected from $50 --> $ 9 units
number of $12 tickets sold --> 15/12 unit = 1.25 units
number of $30 tickets sold --> 36/30 unit = 1.2 units
number of $50 tickets sold --> 9/50 unit = 0.18 unit
0.05 unit --> 5
0.18 unit --> 18

Number of $50 tickets sold = 18

cheers.

[MathIzzzFun]

2632parent:

Hi, can someone help me in this question ? :siao:


1) A shopkeeper had some markers in red and blue. If 50 red markers and 25 blue markers were sold each week, there would be 500 red markers left when all the blue markers were sold. If 25 red markers and 50 blue markers were sold each week, there would be 800 red markers left when all the blue markers were sold. How many markers did the shopkeeper have at first?



:thankyou:

Hi
If 50 red & 25 blue markers sold, 500 red markers left :
sold, red markers : blue markers = 2 : 1 = 4u : 2u
red markers = 4u + 500
blue markers = 2u
Total --> 6u + 500
If 25 red & 50 blue markers sold, 800 red markers left:
sold, red markers : blue markers = 1u : 2u
red markers = 1u + 800
blue markers = 2u

red markers: 4u + 500 = 1u + 800, 1u --> 100

Total number of markers = 6 x 100 + 500 = 1100

cheers.

[2632parent]

Thank you KaisuGrandMaster for your fast response.


I don’t understand in line 2 the unit of the red marker is change to 4u instead of 2u?
Can you kindly explain? Thank you.

[MathIzzzFun]

2632parent:

Thank you KaisuGrandMaster for your fast response.


I don't understand in line 2 the unit of the red marker is change to 4u instead of 2u?
Can you kindly explain? Thank you.

Hi

in both cases, ALL the blue markers were sold, ie the total number of blue markers sold must be the same.

In both cases,
total number of markers
= red markers + blue markers
= (red markers sold + red markers left) + blue markers sold
= (4u + 500) + 2u ---- case 1
= (1u + 800) + 2u ---- case 2


cheers.

[peggy]

Please assist with this.


Mrs Yeo bought some cakes for her class pupils. The girls received twice as many as the boys. There were an equal number of boys and girls in her class. Each boy ate 4/7 of the cake and they finished all the cakes given to them. Each girl ate 1/3 of the cake and they had 8 1/3 cakes left. How many cakes did Mrs Yeo buy?

Thanks.

[MathIzzzFun]

peggy:

Please assist with this.


Mrs Yeo bought some cakes for her class pupils. The girls received twice as many as the boys. There were an equal number of boys and girls in her class. Each boy ate 4/7 of the cake and they finished all the cakes given to them. Each girl ate 1/3 of the cake and they had 8 1/3 cakes left. How many cakes did Mrs Yeo buy?

Thanks.

Hi

please confirm whether it is 8 1/3 cakes or 8 1/2 cakes?
I am assuming 8 1/2 cakes...


cakes eaten by boys : girls = 4/7 : 1/3 = 12 units : 7 units
since the boys ate all the cakes, the number of cakes the boys received is also 12 units
Cakes received by boys : girls = 12 units : 24 units
cakes left by girls --> 24 unit - 7 units = 17 units
17 units --> 8 1/2 cakes = 17/2 cakes
1 unit --> 1/2 cake
total number of cakes --> 36 x 1/2 = 18 cakes

** numbers in the question is not properly set cos the number of boys/girls is not a whole number. Changing the \"8 1/2 cakes\" to \"11 1/3 cakes\" will give a sane solution**

cheers.