Fr pints for yall i saw this and thought i would do it to l o l​

Has anyone here taken the orela elementary education subtest 2 (103)? if so can you link me videos, practice tests, or methods on what you did to pass it?

Why did the following change occur? the snow that covered the ground all winter began to melt tempatures rose and flowers started to bloom

Raul has one solution that is 20% acid by volume and one solution that is 50% acid by volume. he plans to mix together some of each solution to create 30 milliliters of a solution that is 40% acid by volume. how many milliliters of the 20% acid solution should raul use to create the 40% acid solution? can someone explain this to me? i know that the answer is 10 milliliters, but i don't know how to get it.