Question

A box contains balls of black, blue and green colours. If the ratio of black and blue balls is 5:6 and the ratio of blue and green balls is 3:5, then find the ratio of black and green balls.

Answer 1

Given ratio of black and blue balls is 5:6

$\therefore$ let number of black balls = 5$x$ and number of blue balls = 6$x$

and ratio of blue and green balls is 3:5

$\therefore$ let number of blue balls = $3y$ and number of green balls = $5y$ (1 mark)

$\therefore$ $6x$ = $3y$ ($\because$ Both of them are number of blue balls)

$\Rightarrow$ $y$ = 2$x$--------(1) (1 mark)

Now substituting $y$ in 'number of green balls' we get

number of green balls = $5y$

= $5\times$$2x$

= 10$x$

$\therefore$ Number of black balls : number of green balls = 5$x$ : 10$x$ = 1 : 2 (1 mark)