<PRE><B>Question 321345</B>
•	1) Let the amount to be added be x grams.

0.1 (400) + 0.2x = 0.12( 400 + x)

40 + 0.2x = 48 + 0.12x

0.2x - 0.12x = 48 - 40 = 8

0.08x = 8
x = 8/0.08 = 100 grams ANSWER 

2) 0.15( 800) + x = 0.2 ( 800 +x)

120 + x = 160 + 0.2x

0.8x = 40
x = 40/0.8 = 50 grams ANSWER

3) 0.12(10) + 5x = 0.14 ( 15)

1.2 + 5x = 2.1
5x = 0.9
x = 0.9/5 = 0.18 

Answer is 5 gallons of 18% alcohol 

4) 0.6 (200) = 120
0.2(300) =60
total 500 = 180
180/500 X 100 = 36% acid 

5) 0.1(20) = .04 ( 20 + x)

2 = 0.8 + 0.04x

1.2 = 0.04x
x = 1.2/0.04 = 30 litres

6) 0.6( 25) + x = 0.75 ( 25 + x)
15+ x = 18.75 + 0.75x
3.75 = 0.25x
x = 3.75/0.25 = 375/25 = 15 litres

7) 40% of 100 = 40 kilos
To get 50% solution answer is 100 - 80 = 20 kilograms


hehehe</PRE>