Let be "x" the original volume of the solution (in milliliters) before the acid was added and "y" the volume of the solution (in milliliters) after the addition of the acid.

Set up a system of equations:

$\left \{ {{x+y=90} \atop {y=3x+3}} \right.$

Applying the Substitution Method, you can substitute the second equation into the first equation and then solve for "x":

$x+y=90\\\\x+(3x+3)=90\\\\4x+3=90\\\\x=21.75$

6 0

3 years ago

30 drinkers were asked whether they like coffee or tea.

Keith_Richards [23]

Answer:

a)22

b)7

c)8

Step-by-step explanation: its really complicated so ill try my best.

so the say 11 like both coffee and tea so that means that they also added 11 to

the other two sections. so if we take 11 away from 18 we get 7, and that's how many people like coffee and not tea. to get answer c) we need to also subtract 11 from 15, which gets us 4. so we have 11 plus 4 plus 7. and that gets us 22. so 30 subtract 22 gets us 8 so 8 people don't like tea or coffee. 22 is also the answer to a). did you get that? i hope so

3 0

3 years ago