Answer:
The chemist needs to add 400mL of 40% solution.
Step-by-step explanation:
The equation

gives the percent concentration
of the final mixture, when
mL of the 40% solution are added.
Now we are asked, how many milliliters
of the 40% solution should the chemist add to get final percent concentration
; this is just a matter of solving the equation

and we solve it the following way:

Thus, the chemist needs 400mL of 40% solution to get 30% concentration of the final mixture.
Answer:
B
Step-by-step explanation:
X=9
Y=-4
Answer:
Option D is correct.
VS = 20 units.
Step-by-step explanation:
The complete question is contained in the attached image to this answer.
From the image attached and the additional information about the triangles, it is evident that that triangle VSW is similar to triangle QSR.
Hence, we can write the ratio as
(VS/QS) = (VW/QR)
VS = 2a
QS = 2 × VS = 2 × 2a = 4a
VW = 2a - 2
QR = 3a + 6
(2a)/(4a) = (2a - 2)/(3a + 6)
Cross multiplying,
2a (3a + 6) = 4a (2a - 2)
3a + 6 = 2 (2a - 2)
3a + 6 = 4a - 4
4a - 3a = 6 + 4
a = 10
VS = 2a = 20 units.
Hope this Helps!!!
Answer:
The answer is 0.
Step-by-step explanation:
HOPE THIS HELPS!!!
The LCD is 72
8/9 = 64/72
7/8 = 63/72