Question

What quantity of 70 per cent acid solution must be mixed with a 25 solution to produce 540 mL of a 50 per cent solution?

Answer 1

you seem to have alot of these, how are you ever to go thru them efficiently?

Answer 2

i got a formula worked out for these

Answer 3

im hoping someone will tell me a formula to help me out, most ppl on here usually do that
or show me how to get the answer

Answer 4

s + t = 540 ; *-.25
s(.7) + t(.25) = 540(.5)


-s(.25) - t(.25)= 540(-.25)
s(.7) + t(.25) = 540(.5)
--------------------------
s(.7-.25) = 540(.5-.25)

s = 540(.5-.25)/(.7-.25)

Answer 5

we haven't went over this in class yet, we start word problems next week, these are practice problems given to see how much we know

Answer 6

that gives me 300 of 70%

Answer 7

why is it -.25

Answer 8

to get rid of the t(.25) we need to multiply the top by -.25

Answer 9

you see how it cancels out?

Answer 10

i read a book from my library called something like: how to solve word problems. becasue tey used to be and sometimes still are my weak point

Answer 11

who is the author?

Answer 12

cant recall, some old dead guy i think

Answer 13

lol, yeah i've never been good at word problems, i'm even worse at percentages and when you put them together it's a little hard for me to comprehend until the light bulb comes on and then i get it

Answer 14

but math has always been that way for me, i just sit in class and try to follow until the light bulb comes on

Answer 15

i was like that in stats class, memorizing formulas aint for me; and about 2 weeks in i started to understand it better

Answer 16

can you help me with my other problem about fixed cost and unit cost.... im not sure what fixed cost means....