Q&A - P5 Math

[Herbie]

blueymum:

Dear all,


Appreciate your help in the following question:

A concrete mixer has a mixture of cement and sand. If 5.3 litres of cement were added, 75% of the mixture would be sand.
If 57.8litres of cement were added, 40% of the content will be sand.
Find the volume of cement in the mixture.

Thanks much!

15%=0.4 litres of cement
75%= 2 litres of cement

[MathIzzzFun]

blueymum:

Dear all,


Appreciate your help in the following question:

A concrete mixer has a mixture of cement and sand. If 5.3 litres of cement were added, 75% of the mixture would be sand.
If 57.8litres of cement were added, 40% of the content will be sand.
Find the volume of cement in the mixture.

Thanks much!

Hi

http://i56.tinypic.com/5uicub.jpg\">

cheers.

[Winx5015]

http://i52.tinypic.com/1z2f42p.jpg\">

[tianzhu]

Hi


a+b+d+f ---------360 (sum of interior angles in a 4 sided figure)

c+e+g -------180 (triangle)

a+b+c+d+e+f+g ------ 540

Divide the 6 sided figure (blue) into 4 triangles.

u+v+w+x+y+z --------4*180 -------720

Best wishes

[Essential]

Hi, need some help to solve this question.

The ration of Ben’s cards to Benny’s cards was 3:4 After Ben bought another 9 cards and Benny lost 18 cards , the ration became 3:2. Find the total number of cards Ben and Benny had at first.

[Essential]

Mathizzfun, could you help me with this question?

Rosie, sandy and Tabby shared a box of cards. Rosie took 1/5 of th total number of cards and another 12 cards. Sandy took 50% of the remaining cards in the box another 13 cards . Tabby took the last 27 cards in the box. How many cards were there in the box at first?

[MathIzzzFun]

Essential:

Mathizzfun, could you help me with this question?

Rosie, sandy and Tabby shared a box of cards. Rosie took 1/5 of th total number of cards and another 12 cards. Sandy took 50% of the remaining cards in the box another 13 cards . Tabby took the last 27 cards in the box. How many cards were there in the box at first?

Hi

work backwards..

13+27 = 40 = 50% of remaining cards ,
remaining cards after Rosie took = 2 x 40 = 80
80 + 12 = 4/5 of total number of cards =92
Total number of cards in the box = 5/4 x 92 = 115

cheers.

[MathIzzzFun]

Essential:

Hi, need some help to solve this question.

The ration of Ben's cards to Benny's cards was 3:4 After Ben bought another 9 cards and Benny lost 18 cards , the ration became 3:2. Find the total number of cards Ben and Benny had at first.

Hi

At first, Ben : Benny = 3u : 4u

After Ben bought another 9 cards and Benny lost 18,
Ben : Benny = 3u + 9 : 4u - 18 = 3 : 2

Cross multiply-
2(3u+9) = 3(4u-18)
6u + 18 = 12u - 54
6u = 72, 1u = 12

3u = 36, 4u = 48. Ben had 36 cards and Benny had 48 cards at first.

cheers.

[Essential]

Hi MathIzzfun, thank you so much for your replied.

[MathIzzzFun]

Essential:

Hi MathIzzfun, thank you so much for your replied.

u r welcome

cheers.