Three friends, Amina, Brian, and Chebet, invest in a business in the ratio 3:5:2. They make a profit of 12,000 shillings. How much does each person receive? Also, how many kilograms of maize flour wer

The ratio of maize flour to millet is $5:3$.
We are given that $24 \text{ kg}$ of millet were used. Let $M$ be the amount of maize flour used.

The amount of maize flour used was $\boxed{\text{40 kg}}$.

To prepare for twice as many students, the amount of each ingredient must be doubled.
From part (a), maize flour used was $40 \text{ kg}$ and millet used was $24 \text{ kg}$.

New maize flour needed:

New millet needed:

For twice as many students, the school will use $\boxed{\text{80 kg of maize flour and 48 kg of millet}}$.

:
Three friends, Amina, Brian, and Chebet, invest in a business in the ratio $3:5:2$. They make a profit of 12,000 shillings. How much does each person receive?

The investment ratio is Amina : Brian : Chebet = $3:5:2$.
Total parts = $3 + 5 + 2 = 10$ parts.

Amina's share = $\frac{\text{Amina's ratio part}}{\text{Total ratio parts}} \times \text{Total profit}$

Brian's share = $\frac{\text{Brian's ratio part}}{\text{Total ratio parts}} \times \text{Total profit}$

Chebet's share = $\frac{\text{Chebet's ratio part}}{\text{Total ratio parts}} \times \text{Total profit}$

Amina receives $\boxed{\text{3,600 shillings}}$, Brian receives $\boxed{\text{6,000 shillings}}$, and Chebet receives $\boxed{\text{2,400 shillings}}$.