Tutor MathsGuru: Ask me for your burning Maths questions!

[MathIzzzFun]

Superbugs:

P5 question:

Mr Tan had some oranges for sale. The first customer bought 1/2 of the oranges and received 8 oranges free. The second customer bought 45% of the remaining and received 5 free oranges free. The third customer bought 70% of the remaining oranges and received 3 oranges free. Mr Tan then had 1 dozen oranges left. How many oranges did he have at first?

This is what I gathered from the question but I can't solve it, pls help:
1st Customer bought =1/2u+ 8 oranges
Remaining =1/2u- 8 oranges
2nd Customer bought = 45% of (1/2u-8 oranges)
Remaining = 55% of (1/2u-8oranges)
3rd Customer bought = 70% of 55% of (1/2u-8oranges)
Remaining = 30% of 55% of (1/2u-8 oranges)= 12 oranges
1u=16
Pls help as I am unable to get d answer. Tks

Hi

Work backwards to get to the initial number.

Steps:
Quantity Left ---- Quantity Bought
Initial ---- 1st: ½ Initial + 8

½ initial–8=R1 ---- 2nd : 45% of R1 + 5

55% of R1-5=R2 ---- 3rd: 70% of R2 + 3

30% of R2- 3 = 12

work backwards,

30% of R2 = 15, R2 = 15/3 x 10 = 50

55% of R1 – 5 = R2 = 50, R1 = 55/55 x 100 = 100

½ initial -8 = R1 = 100, Initial = 108 x 2 = 216

cheers.

[MathIzzzFun]

Superbugs:

P5 Question:


Before a game, Azmi and Peiqin had the same no. of pitcure cards. During the first round, Azmi lost 12 of his picture cards to Peiqin. During the second round, Peiqin won 16 picture cards from Azmi. In the end, Peiqin had 3 times as many picture cards as Azmi.

a) How many more picture cards did Peiqin have in the end?
b) How many pitcure cards did both of them have in all?

a)
Azmi= 1u
Peiqin=3u+28

2u=28
1u=14
3u+28=3x14+28=56 picture cards

b) 4u+28=84 picture cards

Part a) is correct but for part b) the answer sheet shows 112? Appreciate help on part b) pls. Tks

hi

http://i52.tinypic.com/2vmaaz4.jpg\">

cheers.

[wahwah]

Hi,

Need help for the following Math Qn. Many thanks in advance.

Andy, Ben, Chris shared a box of marbles. Andy received 3/8 od the marbles. Ben received 3/7 as many marbles as Chris. Andy received 213 more marbles then Ben. How many marbles were there in the box?

[MathIzzzFun]

wahwah:

Hi,

Need help for the following Math Qn. Many thanks in advance.

Andy, Ben, Chris shared a box of marbles. Andy received 3/8 od the marbles. Ben received 3/7 as many marbles as Chris. Andy received 213 more marbles then Ben. How many marbles were there in the box?

Hi

Ben: Chris = 3u:7u

Andy: Andy+Ben+Chris = 3:8
Andy: Ben+Chris = 3: 5 = 6u : 10u (total 16u)

Andy: Ben : Chris = 6u: 3u : 7u
So 6u-3u = 3u= 213, 1u = 213/3 = 71
Total 16u = 16 x 71 = 1136 marbles.

cheers.

[wahwah]

Hi MathIzzzFun,

Thanks for the solution!

[ozora]

Need help. Unable to comprehend " with the same amount of money?" Does it mean $90?

How to solve?
Jane bought some pens at $90. If she was given a discount of 20% on her purchase, she would be able to buy 6 more pens wuth the same amount of money. Find the usual price of 1 pen.

[andante]

Hi,

pls help to solve the following question WITHOUT using simultaneous equation.

There was a total of 2400 red, blue and green marbles in Box A and Box B at first. The number of marbles in Box A was twice the number of marbles in Box B. In Box A, The number of red marbles is 25% of the total number of blue and green marbles. The number of blue and green marbles in Box B is 60% of the total number of marbles in Box B. After transferring some marbles between each other, 25% of the marbles in Box A and 75% of marbles in Box B were red. How many marbles were there in Box A after the change?

[MathIzzzFun]

ozora:

Need help. Unable to comprehend \" with the same amount of money?\" Does it mean $90?

How to solve?
Jane bought some pens at $90. If she was given a discount of 20% on her purchase, she would be able to buy 6 more pens with the same amount of money. Find the usual price of 1 pen.

Hi

Discount of 20% = $90 x 0.2 = $ 18
1 pen = $ 18/6 = $3 = 80% of original price

So original price = 10/8 x $3 = $ 3.75 / pen

cheers.

[MathIzzzFun]

wahwah:

Hi MathIzzzFun,

Thanks for the solution!

u r welcome

cheers.

[MathIzzzFun]

andante:

Hi,

pls help to solve the following question WITHOUT using simultaneous equation.

There was a total of 2400 red, blue and green marbles in Box A and Box B at first. The number of marbles in Box A was twice the number of marbles in Box B. In Box A, The number of red marbles is 25% of the total number of blue and green marbles. The number of blue and green marbles in Box B is 60% of the total number of marbles in Box B. After transferring some marbles between each other, 25% of the marbles in Box A and 75% of marbles in Box B were red. How many marbles were there in Box A after the change?

Hi

hope this helps

http://www.flickr.com/photos/62167097@N02/5997248173/in/photostream

cheers.