It depends on how well the rest of the class does. A safe bet is usually a 93 for an A.
1) Let x be the original speed that he was driving;
x mph ---> 1.5 hours
x+44 mph --> 2.5 hours
1.5x + 2.5(x+44)=206
1.5x+2.5x+110=206
4x=206-110
4x=96
x=24
Therefore, he was travelling at 24 mph in the fog.
2) Let x be the speed of 1 snail,
The other snail travels at the speed of x+1 cm/min
23x+23(x+1)=391 <-- solve for x
23x+23x+23=391
46x=368
x=368/46
x=8
Therefore one of the snail travels at 8 cm/min while the other goes at 9 cm/min
7) Let x be one crew
Then the other crew would be working at x+0.5
3.2x+3.2(x0.5)=8 <-- solve for x
3.2x+1.6x=8
4.8x=8
x=8/4.8
x=1.6666 or 1.7 miles
Therefore, one of the crew does 1.7 miles per day and the other crew does (0.5*1.7)=0.85 miles
Hope I helped :)
Answer:

Step-by-step explanation:
Given that,
Radius of the cone, r = 5 units
Height of the cone, h = 6 units
We need to find the volume of the cone. The formula for the volume of the cone is given by :

Substitute all the values,

So, the volume of the cone is
.
Answer:
x=8
Step-by-step explanation:
You would set them equal to each other to get 9x-13=6x+11.
You would them move 6x over so -6x on both sides. This would then get you 3x-13=11.
Then move the -13 over so add 13 to both sides to get 3x=24
Then get x by itself so divide by 3 to get x=24/3.
Then that simplified is 8
Answer:

Step-by-step explanation:
So we have the system of equations:

And we want to multiply the first equation by some constant such that the resulting equation matches the coefficient of [x] in the second equation.
We can see that the coefficient of x in the second equation is 15.
So, to match 15, we must multiply the first equation by 3. So:

Multiply:

And we're done!