Please can I have an explanation also, I am terrible at these kinds of questions!

Q- A bag contain red, yellow and blue beads.

The ratio of red beads to yellow beads is 2:3
The ratio of yellow beads to blue beads is 5:4

Work out what fraction of the beads are red.

Respuesta :

Answer:

The fraction of the beads that are red is

Step-by-step explanation:

Algebraic Expressions

A bag contains red (r), yellow (y), and blue (b) beads. We are given the following ratios:

r:y = 2:3

y:b = 5:4

We are required to find r:s, where s is the total of beads in the bag, or

s = r + y + b

Thus, we need to calculate:

[tex]\displaystyle \frac{r}{r+y+b} \qquad\qquad [1][/tex]

Knowing that:

[tex]\displaystyle \frac{r}{y}=\frac{2}{3} \qquad\qquad [2][/tex]

[tex]\displaystyle \frac{y}{b}=\frac{5}{4}[/tex]

Multiplying the equations above:

[tex]\displaystyle \frac{r}{y}\frac{y}{b}=\frac{2}{3}\frac{5}{4}[/tex]

Simplifying:

[tex]\displaystyle \frac{r}{b}=\frac{5}{6} \qquad\qquad [3][/tex]

Dividing [1] by r:

[tex]\displaystyle \frac{r}{r+y+b}=\displaystyle \frac{1}{1+y/r+b/r}[/tex]

Substituting from [2] and [3]:

[tex]\displaystyle \frac{r}{r+y+b}=\displaystyle \frac{1}{1+3/2+6/5}[/tex]

Operating:

[tex]\displaystyle \frac{r}{r+y+b}=\displaystyle \frac{1}{\frac{10+3*5+6*2}{10}}[/tex]

[tex]\displaystyle \frac{r}{r+y+b}=\displaystyle \frac{10}{10+15+12}[/tex]

[tex]\displaystyle \frac{r}{r+y+b}=\displaystyle \frac{10}{37}[/tex]

The fraction of the beads that are red is [tex]\mathbf{\frac{10}{37}}[/tex]