Q&A - P5 Math
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Hi Maths Hub,
Thanks so much for the prompt solution! -
Hi, need help to answer the following questions from NanHua 2011 SA2 Paper 2.
Q1. A quarter of Jovern’s mass is twice that of Evelyn’s mass. Find the ratio of Eveyln’s mass to Jovern’s mass.
Q6. 36 scouts were told to line up in a row along one side of the square-shaped Assembly Ground from corner to corner at an equal spacing of 1.2m apart to play a game.
Just before the game, 7 of them had to leave and help their teacher with some chores. As a result, the remaining scouts had to line up along the same side of the Assembly Ground at a new equal spacing.
What was the new spacing between 2 scouts?
Q13. Hannah collected $6720 from the sale of some dresses and blouses. The ratio of the price of a dress to the price of a blouse is 5:1. Each blouse costs $5. Even the total number of blouses sold made up 20% of the total number of dresses and blouses sold, how many dresses were sold by Hannah?
Q15. The figure below shows Tap A, Tap B and an empty tank with a capacity of 96.8 litres. Water flows from Tap A at 6.4 litres per minute and Tap B 5.6 litres per minute.
Tap A was turned on first. Tap B was turned on 2 minutes later. The taps were turned off at the same time when the tank was completely full without overflowing.
How much water flowed from Tap B?
My DD answer:
Tap A, 2 mins – 6.4l X 2 = 12.8l
Both taps, 3 mins – 12.8l + 6.4l + 5.6l = 24.8l
At 4 mins – 24.8l + 12l = 36.8l
At 5 mins – 36.8l + 12l = 48.8l
At 7 mins – 48.8l + (12l X2) = 72.8l
At 9 mins – 72.8l + 24l = 96.8l
Tap B – (9 mins – 2 mins) X 5.6l = 39.2l
Is there a shorter way to answer this Q?
Thanks! -
Dad8282:
Q1. A quarter of Jovern’s mass is twice that of Evelyn’s mass. Find the ratio of Eveyln’s mass to Jovern’s mass.Hi, need help to answer the following questions from NanHua 2011 SA2 Paper 2.
Q1. A quarter of Jovern’s mass is twice that of Evelyn’s mass. Find the ratio of Eveyln’s mass to Jovern’s mass.
Q6. 36 scouts were told to line up in a row along one side of the square-shaped Assembly Ground from corner to corner at an equal spacing of 1.2m apart to play a game.
Just before the game, 7 of them had to leave and help their teacher with some chores. As a result, the remaining scouts had to line up along the same side of the Assembly Ground at a new equal spacing.
What was the new spacing between 2 scouts?
Q13. Hannah collected $6720 from the sale of some dresses and blouses. The ratio of the price of a dress to the price of a blouse is 5:1. Each blouse costs $5. Even the total number of blouses sold made up 20% of the total number of dresses and blouses sold, how many dresses were sold by Hannah?
Q15. The figure below shows Tap A, Tap B and an empty tank with a capacity of 96.8 litres. Water flows from Tap A at 6.4 litres per minute and Tap B 5.6 litres per minute.
Tap A was turned on first. Tap B was turned on 2 minutes later. The taps were turned off at the same time when the tank was completely full without overflowing.
How much water flowed from Tap B?
My DD answer:
Tap A, 2 mins – 6.4l X 2 = 12.8l
Both taps, 3 mins – 12.8l + 6.4l + 5.6l = 24.8l
At 4 mins – 24.8l + 12l = 36.8l
At 5 mins – 36.8l + 12l = 48.8l
At 7 mins – 48.8l + (12l X2) = 72.8l
At 9 mins – 72.8l + 24l = 96.8l
Tap B – (9 mins – 2 mins) X 5.6l = 39.2l
Is there a shorter way to answer this Q?
Thanks!
Since a quarter of Jovern’s mass is twice that of Evelyn’s, an eighth of Jovern mass is same as that of Evelyn’s. Therefore ratio = 1 : 8
Q6. 36 scouts were told to line up in a row along one side of the square-shaped Assembly Ground from corner to corner at an equal spacing of 1.2m apart to play a game.
Just before the game, 7 of them had to leave and help their teacher with some chores. As a result, the remaining scouts had to line up along the same side of the Assembly Ground at a new equal spacing.
What was the new spacing between 2 scouts?
Number of Spaces between 36 scouts --> 35 spaces
Length of the line --> 35 × 1.2 = 42 m
Number of Spaces between 29 scouts --> 28 spaces
New Spacing --> 42 ÷ 28 = 1.5 m
Q13. Hannah collected $6720 from the sale of some dresses and blouses. The ratio of the price of a dress to the price of a blouse is 5:1. Each blouse costs $5. Even the total number of blouses sold made up 20% of the total number of dresses and blouses sold, how many dresses were sold by Hannah?
Price of Blouse --> $5
Price of Dress --> $25
Since the total number of blouses sold made up 20% of the total number, the ratio of blouses sold: dresses sold = 1 : 4
We use grouping method to solve this, with each group having 4 dresses and 1 blouse. The cost of each group is 5 + 4 × 25 = $105
Number of groups --> 6720 ÷ 105 = 64
Number of dresses sold --> 64 × 4 = 256
Q15. The figure below shows Tap A, Tap B and an empty tank with a capacity of 96.8 litres. Water flows from Tap A at 6.4 litres per minute and Tap B 5.6 litres per minute.
Tap A was turned on first. Tap B was turned on 2 minutes later. The taps were turned off at the same time when the tank was completely full without overflowing.
How much water flowed from Tap B?
After 2 min, 96.8 – 6.4× 2 = 84 litres left.
After the 2 min, every min, both A and B will fill the tank at a combined rate of 5.6 + 6.4 = 12 litres.
Number of min both taps are on to fill up the 84 litres --> 84 ÷ 12 = 7 min
Therefore, A was on for 9 min and B was on for 7 min.
Amount of water flowed from tap B --> 7 × 5.6 = 39.2 litres -
Hi Maths Hub,
:thankyou: for the fast response! -
Hi Maths hub ,
Thank you for your help -
Hi Maths hub ,
Thank you for your help -
hi all,
need help on this:
how to solve this using model?
1. 25% of Browns money is the same as 20% of Charlie’s Money. Express Brown’s money as a fraction of their total amount of money.
2.
Figure : 1, 2, 3, 4, …,10,…
Sequence: 5, 12, 21, 32, …, 140,…
what figure has the number 10197?
many thanks
shawnlim88
THank you -
Hi shawnlim88
1) For this type of question, you have to make the numerator of Browns and Charlie the same. In this case, it is 1 unit.
http://i45.tinypic.com/14j52sl.jpg\">
Then total amount of money is = 9units.
Ans: Brown's money / total amt of money = 4/9
2) Figure 1 2 3 4 ..... 10
Sequence 5 12 21 32 ......140
Sequence = figure x (figure + 4)
Eg for figure 10:
Sequence = 10 x (10 + 4) = 140
For sequence = 10197,
it can be seen that 100 x 104 = 10400 (which is around 10197), the answer for the figure should be around this value.
Hence, by trial and error, figure is 99. (99 x 103 = 10197).
Thanks -
shawnlim88:
Q1hi all,
need help on this:
how to solve this using model?
1. 25% of Browns money is the same as 20% of Charlie's Money. Express Brown's money as a fraction of their total amount of money.
2.
Figure : 1, 2, 3, 4, ....,10,..
Sequence: 5, 12, 21, 32, .., 140,.....
what figure has the number 10197?
many thanks
shawnlim88
THank you
1/4 Brown's money = 1/5 Charlie's money
Brown's money --> 4 units
Charlie's money --> 5 units
Total --> 9 units
Brown's money as a fraction of the total amount of money = 4/9
Q2.
Add 4 to each number --> 9, 16, 25, 36 ... which is
3²,4², 5², 6² …
so, the sequence for figure number N = (N+2)²-4
10197+4 = 10201 = 101 x 101
101-2=99
Figure 99 = 10197
cheers. -
Dear neowanz & MathIzzzFun
thanks for the help.
cheers