Boy and Girl sells mixtures of almonds and raisins. A kilogram of almonds and raisins cost $300 and $125, respectively. If the final cost of the mixture is $1,400 and the mixture contains 7.5kg of the raisins, how many kilograms of almonds were mixed?

well, just add up the costs:

125(7.5) + 300x = 1400(7.5+x)

These must be special gold nuts, at those prices!!!

To find out how many kilograms of almonds were mixed, we need to use a system of equations.

Let's assume that the weight of almonds in the mixture is "x" kilograms.

From the given information, we know that:
1 kilogram of almonds costs $300, so "x" kilograms of almonds will cost 300x dollars.

Also, 7.5 kilograms of raisins cost $125, so 7.5 kilograms of raisins will cost 125 * 7.5 = $937.5.

The total cost of the mixture is $1,400.

Now we can set up the equation:
300x + 937.5 = 1400

Simplifying the equation:
300x = 1400 - 937.5
300x = 462.5

Dividing both sides by 300:
x = 462.5 / 300
x = 1.54

Therefore, 1.54 kilograms of almonds were mixed with 7.5 kilograms of raisins.