Answer:
10 minutes
Step-by-step explanation:
Let's use the variable x for the amount of coins.
The first machine can sort x coins in 15 minutes, so its speed is x/15 coins/minute.
The second machine can sort x coins in 30 minutes, so its speed is x/30 coins/minute.
If we sum the speeds, we have that the speed will be:
speed = (x/15) + (x/30) = (2x + x)/30 = 3x/30 = x/10
The total speed can sort x/10 coins per minute, that is x coins in 10 minutes.
Answer:
9-4/5
5/5 = 1
Step-by-step explanation:
Answer:
9
Step-by-step explanation:
Compare your x2 + y2=81 to the following:
x^2 + y^2 = 81
The " ^ " symbol indicates exponentiation.
Now compare x^2 + y^2 = 81 to
x^2 + y^2 = r^2.
This is the standard equation of a circle of radius r centered at the origin, (0,0). You can see for yourself that 81 must equal r^2.
Taking the square root of 81, we get plus or minus 9.
But the radius must be positive, so we reject the -9 and take +9.
The radius is 9.
Answer:
2
Step-by-step explanation:
To be divisible by 6, an even number must also be divisible by 3. Two of every three even numbers are <em>not</em> divisible by 3, so are not divisible by 6.
