A chemist has80pints of a20%salt sol.How many pints of pure salt must b added to form a sol that is30%salt?

Question

word problem of mixture

Answer 1

Let x be amount of pure salt to be added:

Therefore: 0.3 = [0.2(80)+x]/[80+x] = [16+x]/[80+x]
Or, 24 + 0.3x = 16 + x

Hence, x = [24-16]/[1-0.3] = 8/0.7 = 11 3/7 Pints

Answer 2

80/20 = x/30

solve for x

(80/20)*30 = x
120 = x

therefore 120- 80 = 40

you need to add 40 pints

Answer 3

amount*percent
let x = amount of pure salt
we will then have x+80 total

80*.20 + x(1.00) = .30 (x+80)
1.6 + x = .3x + 24
.7 x = 22.4
x = 32

32 pints

Answer 4

(16+x)/(80+x)=.3
16+x=.3(80+x)
16+x=24+.3x
.7x=8
x=11.428 pints must be added