Answer:
50 (?)
Step-by-step explanation:
because it takes 20 to get to 0 and another 30 to get to 30. added together makes 50
Answer:
hint for next time
Step-by-step explanation:
never ask a a and b question for only 5 points
Answer:
1900 km
Step-by-step explanation:
Let be the volume of 20% solution, the volume of the 60% solution. We want a total volume of 400 mL in the final mixture, so
Each mL of either solution will contribute a corresponding concentration, and in the final mixture we want the 400 mL to have a 40% concentration, which means we should also have
Solve the system and we get .