How many grams of salt must be added to 6 grams of 5% salt to make 30% salt?

Question

I have the answer..need the equation to help me see how to setup this problem for further use. Thanks a bunch.

Answer 1

easy
you should have written (to a solution of 5% salt)
the quantity of salt in 6 grams of a 5% solution is .3 grams.

the amount to add to make a 30% solution can be calculated as x
(,3 +x) /6= 30%
.3 +x=1.8
x= 1.5 grams of salt

Answer 2

Set up the equation like this :

Mass1 * Percent1 + Mass2 * Percent2 = Mass3 * Percent3

Substituting in the values, and letting X = the unknown amount, we have :

X * 100 + 6 * 5 = (X + 6) * 30

100X + 30 = 30X + 180
70X = 150
X = 15 / 7
So you need 15 / 7 grams of 100% salt.

Answer 3

If 5% = 6 gms
Then 30% = 30/5 x 6 = 36gms
The addition = 36-6=30gms.

PS: Sorry, I goofed!

Answer 4

First, you need to determine how much of salt and not-salt is in the mixture.

So, we use the formula that Concentration = Amount of Salt / (Amount of Salt + Non-Salt)

Or, C = S / (N + S) | multiplying both sides by (N+S) gives
C(N+S) = S
CN + CS = S
CN = S (1-C) | dividing both sides by (1-C) and rearranging
S = CN / (1-C)

So, what you need to find is the quantity of non-salt, N, and you can solve for any desired concentration, C.

Checking for accuracy:
6 g of 5% salt means it has 5.7g non-salt (and thus 0.3g salt), so plugging these in:
(0.05)(5.7) / (1-0.05) = .285/.95 = 0.3g salt (the equation works)

So, for N=5.7g and desired concentration of 30%, the total salt needed would be:

S= CN / (1-C) = (0.3)(5.7) / (1-0.3) = 1.71/0.7 = 2.44g

if you started with 0.3g, then you need to add 2.44 - 0.3 = 2.14g.

Answer 5

X = Salt
Y = NonSalt

5%(X) + (95%)Y= 6
X = 5 % * 6 = 0.3
Y = 95% * 6 = 5.7

Current
X/Y = 5/95 = 1/19

Y = 19X

How many a
(X+a)/Y =30/70 = 3/7

(X+a)/Y = 3/7
3Y=7(X+a)
3Y=7X+7a
3(19X)=7X+7a
57X=7X+7a
50X=7a

The ANSWER is

a=(50/7)X ==> x=0.3 =3/10
a= (50/7)(3/10)
a=15/7
a =2.1428571428571428571428571428571

proove
(0.3+2.1428571428571428571428571428571) / 5.7
=(2.4428571428571428571428571428571) / 5.7
= 3/7

(2.4428571428571428571428571428571) + 5.7
=8.1428571428571428571428571428571

2.4428571428571428571428571428571
---------------------------------------------------------- : ===> 30%
8.1428571428571428571428571428571

prooved

Answer 6

correction to previous answerer:

since when you add x grams of sault, the total grams changes as well ..

(0.3 + x)/ (6 + x) = 30%

0.3 + x = 0.3x + 1.8
0.7x = 1.5
x = 15/7