Answer:
240 ml of 1.5% solution and 360 ml of 4% solution should be used.
Step-by-step explanation:
Since a lab assistant needs to create a 600 mL mixture that is 3% hydrochloric acid, and the assistant has solutions of 1.5% and 4% in supply at the lab, to determine the number of milliliters of the 1.5% solution and the number of milliliters of the 4% solution that must be used, the following calculations must be performed:
50 x 0.015 + 50 x 0.04 = 0.75 + 2 = 2.75
40 x 0.015 + 60 x 0.04 = 0.6 + 2.4 = 3
600 x 0.4 = 240
Therefore, 240 ml of 1.5% solution and 360 ml of 4% solution should be used.
its D.
Step-by-step explanation:
let x = miles
we have x miles/ 60mph plus x miles / 40 mph = 1 hour
x/60 + x/40 = 1
we need to calculate 2x for the round trip
calculate common denominator and rewrite the 2 fractions:
2x/120 + 3x/120 = 1
5x= 120
x = 120/5 = 24 miles
24*2 = 48 miles total
check:
1 way would be 48/2 = 24 miles
24/60 = 0.4 hours to drive 24 miles at 60 mph
24/40 = 0.6 hours to drive 24 miles at 40 mph
0.6 +0.4 = 1 hour
