Q&A - PSLE Math

[MathIzzzFun]

anneshirleygilbert:

Hi MathIzzzFun,


I have some trouble interpreting this question:

The sum of 4 numbers is 80.If you add 3 to the first number, subtract 3 from the second number,multiply the third number by 3 d divide the fourth number by 3,the result will be equal.What is the difference between the largest and the smallest of the original numbers.

How do you interpret \"the result will be equal\"? You have made the end of each number equals 15, giving a total of 60. I interpreted it as the end total result is equal to the beginning total of 80 and got a mixed fraction answer. How do you know what's the right way of interpreting the question? We get into such muddles sometimes. Pls help.


hi

Hi
after multiplying 3rd number by 3 --> 3u

1st number --> 3u-3
2nd number --> 3u +3
3rd number --> 1u
4th number --> 9u
Total --> 16u = 80
1u --> 5

1st number --> 12
2nd number --> 18
3rd number --> 5
4th number --> 45

cheers.

\"If you add 3 to the first number, subtract 3 from the second number,multiply the third number by 3 d divide the fourth number by 3,the result will be equal\"--> my interpretation is:
1st number + 3
= 2nd number - 3
= third number x 3
= fourth number/3
= 3u (since the 3rd number was multiplied by 3)
so, this gives,
1st number --> 3u -3
2nd number --> 3u + 3
3rd number --> 3u/3 = 1u
4th number --> 3u x 3 = 9u

cheers.

[Shimmer]

1)At 9a.m, John was cycling from A to B . At the same time, Mary was cycling from Point B to A using the same route as John. Cycling at a speed of 4km/h faster than Mary, John would pass Mary 300 m away from midpoint.

A)What time did that pass each other?
B) If John took another 3 min to reach B, what time would Mary reach B?

[Shimmer]

In the 6A and B,the total number of girls was 100% more than boys. The ratio of boy to girl in 6A is 3:4 and the ratio of boy to girl in 6B is 1:6. If there were 8 more girls in 6a than 6b, find the no. of pupils in 6a.

[Shimmer]

John had $180 more than Ail at first. Both bought a different printer with some money. In the end, Ail was left with $20 more than John. If John’s printer cost 50% more than Ali’s printer,how much does John printer cost?

[MathIzzzFun]

Shimmer:

John had $180 more than Ail at first. Both bought a different printer with some money. In the end, Ail was left with $20 more than John. If John's printer cost 50% more than Ali's printer,how much does John printer cost?

Hi

http://i46.tinypic.com/2aj6wqx.png\">

cheers.

[MathIzzzFun]

Shimmer:

In the 6A and B,the total number of girls was 100% more than boys. The ratio of boy to girl in 6A is 3:4 and the ratio of boy to girl in 6B is 1:6. If there were 8 more girls in 6a than 6b, find the no. of pupils in 6a.

Hi

6A, Boys: Girls = 3:4 --> 9:12
6B, Boys: Girls = 1:6 --> 2:12

There were 8 more girls in 6A than 6B,
6A, Boys: Girls --> 9u + 6 : 12u + 8 -- total --> 21u + 14
6B, Boys: Girls --> 2u : 12u

Total number of girls was 100% more than boys,
24u + 8 = 2 x (11u +6)
1u --> 2

Total number of pupils in 6A --> 21 x 2 + 14 = 56

cheers.

[MathIzzzFun]

Shimmer:

1)At 9a.m, John was cycling from A to B . At the same time, Mary was cycling from Point B to A using the same route as John. Cycling at a speed of 4km/h faster than Mary, John would pass Mary 300 m away from midpoint.

A)What time did that pass each other?
B) If John took another 3 min to reach B, what time would Mary reach B?

Hi

I think similar questions were discussed before.

When John pass Mary, the meeting point X will be nearer to B, and John would have cycled 300m x 2 = 600m more than Mary.
Time taken to pass each other = 600m/(4km/h) = 9 min
They passed each other at 9.09am

John took 3min to cycle the distance BX, Mary took 9 min to cycle the same distance BX.
For distance AX, Mary will take 9/3 x 9 = 27 min
9.09am + 27min --> 9.36am
Mary reached A at 9.36am

cheers.

[Neat]

Hi!


Faye baked some muffins to sell.
2/3 of them were chocolate muffins and the remaining were walnut muffins.
After she had sold 5/6 of the chocolate muffins and 400 walnut muffins, she had 1/6 of the muffins left.

a) How many muffins did she sell altogether?
b) What percentage of the muffins sold were walnut muffins?

Thanks

[MathIzzzFun]

Neat:

Hi!


Faye baked some muffins to sell.
2/3 of them were chocolate muffins and the remaining were walnut muffins.
After she had sold 5/6 of the chocolate muffins and 400 walnut muffins, she had 1/6 of the muffins left.

a) How many muffins did she sell altogether?
b) What percentage of the muffins sold were walnut muffins?

Thanks

Hi

CM : WM = 2:1 --> 12u : 6u (total 18u)
Sold, CM --> 10u, WM --> 400, total sold --> 5/6 of total = 5/6 x 18u = 15u
10u + 400 = 15u, 1u --> 80
..can you continue from here ?

cheers.

[Neat]

MathIzzzFun:

Neat:

Hi!


Faye baked some muffins to sell.
2/3 of them were chocolate muffins and the remaining were walnut muffins.
After she had sold 5/6 of the chocolate muffins and 400 walnut muffins, she had 1/6 of the muffins left.

a) How many muffins did she sell altogether?
b) What percentage of the muffins sold were walnut muffins?

Thanks

Hi

CM : WM = 2:1 --> 12u : 6u (total 18u)
Sold, CM --> 10u, WM --> 400, total sold --> 5/6 of total = 5/6 x 18u = 15u
10u + 400 = 15u, 1u --> 80
..can you continue from here ?

cheers.

[quote]Hi! MathIzzzFun[/quote]Yes, I can.

Thank you so much for your prompt reply.

:thankyou: