Answer:
3. David and Aryana use their phones at the same rate.
4.10 parts of water to 20 parts of cornstarch.
Explanation:
3. First, you have Aryana who uses 160 mins in 4 days. Then there is David who has 120 minutes in 3 days. You want to divide the minutes by days to see how many minutes per day they use their phone. 160/4=40 120/3=40. David and Aryana use their phones at the same rate.
4. First, you have 24c to 12w (c is cornstarch and w is water). If you want to find 20c and what w is, you need to make c into a smaller number. What I mean is that you need to divide the equation as low as it can go, this one happening to be 12. So you do 24 to 12/12 = 2c to 1w. You then multiply the number back up to twenty. so 2*10 = 20 1*10=10. Your final answer is 10 parts of water to 20 parts of cornstarch.