A chemical company makes two brands of antifreeze. The first brand is 45% pure antifreeze, in the second brand is 70% pure antifreeze. in order to obtain 90 gallons of a mixture that contains 60% of pure antifreeze, how many gallons of each brand of antifreeze must be used?

No matter what I do, I cannot figure out this problem.

Use the spider tool located on page 1 of this activity to draw a 12-pointed star for the new logo. (hint: if the spider rotates 360 degrees -- or 720 degrees or 1080 degrees -- she will be facing in the same direction in which she started. when the spider is done drawing, you want her to be facing in the same direction in which she started. she'll be making 12 rotations, all the same size, so each rotation must be some multiple of 360/12 = 30 degrees.) urgently. been stuck on this problem for around 45 minutes now.! it should be easy if you're smart enough