Answer: common difference is 14
Step-by-step explanation:
a,a+d,a+4d
7,7+d,7+4d
(7+d)/7=(7+4d)/(7+d)
(7+d)(7+d)=7(7+4d)
49+14d+d^2=49+28d
d^2-14d=0
d(d-14)=0
d=0 or d-14=0
d=14
Answer:
x=12
Step-by-step explanation:
move the 3 to the other side to get x by itself.
check: 12 + 3 = 15
Let 
be the volume of 20% solution, 
the volume of the 60% solution. We want a total volume of 400 mL in the final mixture, so
Each mL of either solution will contribute a corresponding concentration, and in the final mixture we want the 400 mL to have a 40% concentration, which means we should also have
Solve the system and we get 
.
I apologise, but it is as though that there is some missing necessary information. Perhaps there was an error?
