There are 2 packets of flour, Y & Z.The ratio of the mass of Y to Z is 4:1. If 26g is added to Z,the ratio of the mass of Y to Z is 7:5. Find the mass of the 2 packets at first. Pls show how to solve by model method as i have not learnt algebra. tks

Answer 1

let the mass of Y be 4x
let the mass of Z be x , (notice Y:Z = 4x:x = 4:1 )

new Z = x+26

now Y:Z = 7:5

4x/(x+26) = 7/5
20x = 7x + 182
13x = 182
x = 14
4x = 56

the two packets had a mass of 56 g and 14 g.

Here is the same question from an earlier date
http://www.jiskha.com/display.cgi?id=1313814541
Both drwls and I are giving you an algebraic solution, looking slightly different but in effect containing the same steps.
I don't think a curriculum should present questions when the proper tools have not been taught.
That would be similar to asking somebody to bake a cake, but saying you have to do it without having an oven.

Answer 2

I agree but my teachers don't care and even wrong answers have to be solved by ourselves and I keep getting them wrong again tks to both of you for your help