7x2+x-6 is the correct answer
15% of 20 gal = 0.15 * 20 gal = 3 gal, so the solution contains 3 gal of salt.
If we add <em>x</em> gal of water to the solution, we end up with (20 + <em>x</em>) gal of solution. We want the new mixture to have a concentration of 10%, or
10% of (20 + <em>x</em>) gal = 0.1 * (20 + <em>x</em>) gal = 2 + 0.1<em>x</em> gal
of salt.
The amount of salt in the tank hasn't changed. Solve for <em>x </em>:
2 + 0.1<em>x</em> = 3
0.1<em>x</em> = 1
<em>x</em> = 10 gal
The answer to your question is 10 seconds. I know this because:
distance divided by speed=time
let t=time
t=2*6(30/36)=10
t=10
So, it took Boris a total of 10 seconds to run up the out of service elevator.
Hope this helps!
Answer:
its d
Step-by-step explanation:
he did one task in 2.25 mins so multiply by 10
