$3 chocolate = 12 #### Explanation: So we need to set up an equation for the information we have. I'll be using simultaneous equations.$8 chocolate = x
and
$3 chocolate = y So, Equation 1 : $x$pounds + $y$pounds = 20 pounds $x + y = 20$And equation 2: ($8 times x pounds) + ($3 times y pounds) = 20 pounds times$5
$8 x + 3 y = 100$

Now we need to take equation 1 and make x the subject

$x = 20 - y$

Now we need to sub that into equation 2 to get

$8 \left(20 - y\right) + 3 y = 100$

Simplify to get

$160 - 8 y + 3 y = 100$

$- 8 y + 3 y = 100 - 160$

$- 5 y = - 60$

$y = \frac{- 60}{-} 5$

$y = 12$

Now we sub that into equation 1 with x as the subject

$x = 20 - 12$

$x = 8$

Hope this helped!

Aug 4, 2017

$8$ pounds of $8 chocs and $12$pounds of$3 chocs.

#### Explanation:

Set up a system of equations.

Let the number of $8 pounds be $x$and the number of $3 pounds be $y$
There will be $20$ pounds altogether.

$x + y = 20 \text{ } \Rightarrow y = \left(20 - x\right)$

The value of the $8 chocs will be: $8 x$The value of the $3 chocs will be $3 y$
The total value of the chocs will be $20 \times 5 = 100$

$8 x + 3 y = 100$

Now you can solve the two equations:

$8 x + 3 \left(20 - x\right) = 100 \text{ } \leftarrow$ subst for $y$

$8 x + 60 - 3 x = 100$

$5 x = 100 - 60$

$5 x = 40$

$x = 8$
$y = 12$

$8$ pounds of $8 chocs and $12$pounds of$3 chocs.

Check: $8 \times 8 + 12 \times 3 = 64 + 36 = 100$