Tutor MathsGuru: Ask me for your burning Maths questions!

[livewith_vanilla]

Alan, Brandon, Calvin and Darren shared $192. Darren received 1/7 of the total amount of money received by Alan, Brandon and Calvin. Alan received 1/2 of the total amount of money received by Brandon and Calvin. Brandon received 2/5 as much money as Calvin. How much did Brandon receive ?


A+B+C
1:7
3:21

A:B+C
1:2
7:14

B:C
2:5
4:10

21u+3u=24u

24u -> 192
4u ->192/6=32

My answer is $ 32.

[livewith_vanilla]

starlight1968sg:

Sorry: it is 156 pens! :oops:

Its okay.

Before:
R:B
7:6

After:
R:B
7:3


7+6=13

13u-> 156
1u-> 156/13=12 (Difference between number of red pens and blue pens.)
7u-> 84 (Red pens)
6u-> 72 (Blue pens)


7-3=4 (Units difference (after) between Red and Blue pens)

Since Mary gave away the same number of blue and red pens, the difference between red and blue pens are the same as before. Hence,

4u->12
1u->3
3u->9

72-9=63
63x2=126

Ans:126 pens

[starlight1968sg]

livewith_vanilla:

starlight1968sg:

Sorry: it is 156 pens! :oops:

Its okay.

Before: After:
R:B R:B
7:6 7:3


7+6=13

13u-> 156
1u-> 156/13=12 (Difference between number of red pens and blue pens.)
7u-> 84 (Red pens)
6u-> 72 (Blue pens)


7-3=4 (Units difference (after) between Red and Blue pens)

Since Mary gave away the same number of blue and red pens, the difference between red and blue pens are the same. Hence,

4u->12
1u->3
3u->9

72-9=63
63x2=129

Ans:129 pens

Thanks, yes the ans is 126 (ie 63*2).
No prob getting 84 red pens and 72 blue pens. Somehow, I got stuck in the second part.

[livewith_vanilla]

starlight1968sg:

livewith_vanilla:

[quote=\"starlight1968sg\"]Sorry: it is 156 pens! :oops:

Its okay.

Before: After:
R:B R:B
7:6 7:3


7+6=13

13u-> 156
1u-> 156/13=12 (Difference between number of red pens and blue pens.)
7u-> 84 (Red pens)
6u-> 72 (Blue pens)


7-3=4 (Units difference (after) between Red and Blue pens)

Since Mary gave away the same number of blue and red pens, the difference between red and blue pens are the same. Hence,

4u->12
1u->3
3u->9

72-9=63
63x2=126

Ans:126 pens

[/quote]Thanks, yes the ans is 126 (ie 63*2).
No prob getting 84 red pens and 72 blue pens. Somehow, I got stuck in the second part.[/quote

I got stuck there, but I realised that since Mary gave away the same number of red and blue pens, the difference (pens) between the after ratio and before would be the same.

If you get what I mean and thanks for correcting my careless mistake.


Anything you don't understand?

May I know if you are a primary 5 or primary 6

[starlight1968sg]

haha.. wish I am p5 or p6! am a working mum who did not study real hard when I was young! :roll:

[livewith_vanilla]

starlight1968sg:

haha.. wish I am p5 or p6! am a working mum who did not study real hard when I was young! :roll:

Beg my ignorance, :oops: :oops:

So you have a child who's in that level I suppose ?

The questions seem to be harder these days, I'm a p6 and the p5 questions seems to be getting harder(weird I said that but its true in a sense) !

[kancheongmum]

hi all need help in this speed question

last monday morning, edward walked from home to school. for the first 2 mins, he was walking at an average speed of 40 m/min. when he realized that he was going to be late by 3 mins, he quickly increased his speed by 10m/min. as a result, he was early by 1 min. find the distance between his home to school. (ans 880 m)
thanks

[maths6a]

starlight1968sg:

Hi folks,

I need some help here:

Mary has a total of 156 red and blue pens in the ratio 7:6. After giving away an equal number of each type of pen, the number of red and blue pens left was in the ratio 7:3. How many pens did she did away altogether?

Many thanks.

Since equal number of pens were given away, the DIFFERENCE between each type of pen will STAY the SAME.
7-6 = 1 unit (difference at first)
7 + 3 = 13 (total number of units at first)
156/13 =12 (1 unit at first)
7-3 = 4 (difference after)
12/4 = 3 (1 unit after)
7+3 = 10 (total number of units after)
10 x 3 = 30 were left
156 - 30 = 126 were given away in all

[blessedami]

kancheongmum:

hi all need help in this speed question

last monday morning, edward walked from home to school. for the first 2 mins, he was walking at an average speed of 40 m/min. when he realized that he was going to be late by 3 mins, he quickly increased his speed by 10m/min. as a result, he was early by 1 min. find the distance between his home to school. (ans 880 m)
thanks

Hi kancheongmum,
My DS got the answer like this:
He used algebra:

Let the time from which he left home to the expected time at school be x

Let Distance between school and home be y

Since he will reach 3 mins late if he travels the whole distance at 40m/min

(x+3)min x 40m/min= y m
(40x+120) = y m ( Equation 1 )

If he travels the first 2 mins at 40m/min and then travels the rest at
50m/min and be 1 min early,

2min x 40m/min + (x-2-1) min x 50m/min= y m
80m + ( x- 3 ) min x 50 m/min = y m
80m + ( 50x – 150 ) m = y m ( Equation 2 )

Comparing Equations 1 and 2

(40x+120) = y m ( Equation 1 )

80m + ( 50x – 150 ) = y m ( Equation 2 )

(40x+120) = 80 m + (50x- 150 )
= (50x+70)
10x = 120+70=190
x= 190÷10= 19 min
y= 80 m + ( 50 m/ min x 19 min- 150 m)
= 80 m + ( 950m- 150 m)
= 80 m + 800m
= 880 m

[maths6a]

kancheongmum:

hi all need help in this speed question

last monday morning, edward walked from home to school. for the first 2 mins, he was walking at an average speed of 40 m/min. when he realized that he was going to be late by 3 mins, he quickly increased his speed by 10m/min. as a result, he was early by 1 min. find the distance between his home to school. (ans 880 m)
thanks

2 min x 40m/min = 80 m already walked

Let the remaining time he has to reach his destination be x min.
Walking at 40 m/min, he will need (x + 3) min so idstance travelled will be
40(x + 3) = 40 x + 120 (D1)

but when he walked at 50 m/min
he will take (x - 1)min
so distance travelled will be
50(x - 1) = 50 x - 50 (D2)

since D1 = D2
40x + 120 = 50x - 50
10 x = 170
x = 17 min
total distance = 17 x 40 + 120 + 80 already travelled
= 880 m