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[Chan09]

Need some help:

In a test, A,B,C and D scored an average of 73.25marks. D score was 60% of A. A scored 4 marks more than C. B scored 27 marks less than A. Calculate B scores?

Ans: 63 marks

[atutor2001]

Chan09:

Need some help:

In a test, A,B,C and D scored an average of 73.25marks. D score was 60% of A. A scored 4 marks more than C. B scored 27 marks less than A. Calculate B scores?

Ans: 63 marks

Let me try using ratio.

60% = 3/5 i.e. D is 3/5 of A

Ratio of D : A = 3U : 5U
Ratio of D : A : C = 3U : 5U : (5U-4)
Ratio of D : A : C : B = 3U : 5U : (5U-4) : (5U-27)

Total score = 73.25 x 4 = 293

Total of 3U, 5U, (5U-4) and (5U-27) must be equal to 293

If we add 4 to (5U-4), it will become 5U
If we add 27 to (5U-27), it will also become 5U
Because of 4 & 27 added, the total will be increased to 293+27+4 =324

Therefore, 3U(D) + 5U(A) + 5U(C with 4 added) + 5U(B with 27 added) = 324

18U = 324
U = 18

B = 5U - 7
= (5x18) - 27
= 63

[jtparent]

Hi another 2 q to seek ur assistance


1. Shaoquan had less than 40 cookies. If he packs them in packets of 5, he will have 2 cookies left. If he packs them in packets of 7, he will be short of 3 cookies. How many cookies does he have?

2. Lee Bin, Vanessa & Sarah had $900 altogether. After Lee Bin spent 3/5 of her money, Vanessa spent 1/2 of her money and Sarah spent 3/7 of her money, the ratio of the amount of money they had left was 2:3:4 respectively. How much did each girl have at 1st?

[MathIzzzFun]

jtparent:

Hi another 2 q to seek ur assistance


1. Shaoquan had less than 40 cookies. If he packs them in packets of 5, he will have 2 cookies left. If he packs them in packets of 7, he will be short of 3 cookies. How many cookies does he have?

2. Lee Bin, Vanessa & Sarah had $900 altogether. After Lee Bin spent 3/5 of her money, Vanessa spent 1/2 of her money and Sarah spent 3/7 of her money, the ratio of the amount of money they had left was 2:3:4 respectively. How much did each girl have at 1st?

Hi

1. If we add 3 more cookies, the total can be packed into packets of 5, and packets of 7 exactly ie the total will be a multiple of both 5 & 7 = 35 (less than 40).

So, number of cookies = 35 - 3 (since we added 3 cookies) = 32.

Alternatively, you could also use the listing method to solve.

2. Amount left:
Lee Bin = 2u = 2/5 of her money, so initially Lee Bin had 5u
Vanessa = 3u = 1/2 of her money, so initially Vanessa had 6u
Sarah = 4u = 4/7 of her money, so initially Sarah had 7u

Total = 5u + 6u + 7u = 18u = $900, 1u = $50

Initially,
Lee Bin had 5 x $50 = $250
Vanessa had 6 x $50 = $300
Sarah had 7 x $50 = $350

cheers.

[jtparent]

MathIzzzFun:

jtparent:

Hi another 2 q to seek ur assistance


1. Shaoquan had less than 40 cookies. If he packs them in packets of 5, he will have 2 cookies left. If he packs them in packets of 7, he will be short of 3 cookies. How many cookies does he have?

2. Lee Bin, Vanessa & Sarah had $900 altogether. After Lee Bin spent 3/5 of her money, Vanessa spent 1/2 of her money and Sarah spent 3/7 of her money, the ratio of the amount of money they had left was 2:3:4 respectively. How much did each girl have at 1st?

Hi

1. If we add 3 more cookies, the total can be packed into packets of 5, and packets of 7 exactly ie the total will be a multiple of both 5 & 7 = 35 (less than 40).

So, number of cookies = 35 - 3 (since we added 3 cookies) = 32.

Alternatively, you could also use the listing method to solve.

2. Amount left:
Lee Bin = 2u = 2/5 of her money, so initially Lee Bin had 5u
Vanessa = 3u = 1/2 of her money, so initially Vanessa had 6u
Sarah = 4u = 4/7 of her money, so initially Sarah had 7u

Total = 5u + 6u + 7u = 18u = $900, 1u = $50

Initially,
Lee Bin had 5 x $50 = $250
Vanessa had 6 x $50 = $300
Sarah had 7 x $50 = $350

cheers.

Tks so much.

The listing method for q1 is it call guess & check method?

BTW re u a tutor / teacher?

[MathIzzzFun]

jtparent:

MathIzzzFun:

[quote=\"jtparent\"]Hi another 2 q to seek ur assistance


1. Shaoquan had less than 40 cookies. If he packs them in packets of 5, he will have 2 cookies left. If he packs them in packets of 7, he will be short of 3 cookies. How many cookies does he have?

2. Lee Bin, Vanessa & Sarah had $900 altogether. After Lee Bin spent 3/5 of her money, Vanessa spent 1/2 of her money and Sarah spent 3/7 of her money, the ratio of the amount of money they had left was 2:3:4 respectively. How much did each girl have at 1st?

Hi

1. If we add 3 more cookies, the total can be packed into packets of 5, and packets of 7 exactly ie the total will be a multiple of both 5 & 7 = 35 (less than 40).

So, number of cookies = 35 - 3 (since we added 3 cookies) = 32.

Alternatively, you could also use the listing method to solve.

2. Amount left:
Lee Bin = 2u = 2/5 of her money, so initially Lee Bin had 5u
Vanessa = 3u = 1/2 of her money, so initially Vanessa had 6u
Sarah = 4u = 4/7 of her money, so initially Sarah had 7u

Total = 5u + 6u + 7u = 18u = $900, 1u = $50

Initially,
Lee Bin had 5 x $50 = $250
Vanessa had 6 x $50 = $300
Sarah had 7 x $50 = $350

cheers.

Tks so much.

The listing method for q1 is it call guess & check method?

BTW re u a tutor / teacher?[/quote]Hi

We can use the listing or systematic listing method -

List the multiples of 5 & 7 and add the remainders as follows:

multiple of 5 : 5 , 10, 15, 20, 25, 30, 35, 40

total = +2 (cos left 2 cookies) : 7, 12, 17, 22, 27, 32, 37

multiple of 7 : 7, 14, 21, 28, 35

total = +4 (cos short of 3 cookies to form another group of 7= remainder 4): 11, 18, 25, 32, 39

By comparing the totals of both, we can see that there is only one match = 32.

cheers.

[2DMommy]

Need help with these two percentage questions :


1) The ratio of Alan’s total marks to that of Benji’s total marks in their Mid-Year Examination
was 4 : 5 . Alan’s marks increased by 50% in the End-of-Year Examination. By what
percentage must Benij’s marks be increased so that their total marks would be equal ?


2) Timothy had a box of strawberry sweets and pineapple sweets. When he added in 30 strawberry
sweets, 20% of the sweets were pineapple sweets. When he added in another 100 pineapple sweets,
60% of the sweets were pineapple sweets. How many strawberry\tsweets were there in the container
at first ?\t\t\t\t\t\t\t\t\t

Thanks !!

[Andrew Lee]

http://i52.tinypic.com/nmzzep.jpg\"> :roll:

[MadScientist]

Here goes…


A) [ 5 / (5+9) ] = 35.71% of the circle is shaded.

B) 168 * 35.71% = 60 sqcm
Since AE = EB, Triangle is an isoceles triangle (ie. two equal sides)
And shaded part is 40% of triangle, therefore, 60 sqcm is 40% of triangle.
Area of triangle DEC = (100/40) x 60 = 150 sqcm

[Adam Ma]

May I know what level of class this problem comes from?