Answer:
Infinite number of solutions.
Step-by-step explanation:
We have the equations,
1. 3x+3y=10
2. -9x-9y= -30
Now, if we multiply equation 1 with -3, we will obtain equation 2.
i.e. -3×(3x+3y)= -3×10
i.e. -9x-9= -30
So, we see that both the equations are same.
The equation 3x+3y=10 will have solution for many values of x and y.
Hence, the system will have infinite number of solutions.
Answer:
The green would take 4 and the blue would take 16 times respectivly. I did it by finding the volumes of the cups in terms of pi, then dividing it by the volume of the sink.
Step-by-step explanation:
So the volume of the whole half sphere is 512pi.
Now we have to find the volumes of the cup.
Equation: 
Blue cup:

It would take 16 times to drain it completly.
Green cup:

It would take 4 times to drain it completly.
Answer:
identical in form or shape
Step-by-step explanation:
two triangles could be congruent as they both have 3 sides.
Answer:
28 short-sleeved shirts were sold and 23 long-sleeved shirts were sold.
Step-by-step explanation:
We can solve this question by a system of equations.
I am going to say that:
x is the number of short-sleeved shirts sold.
y is the number of long-sleeved shirts sold.
A department store sold 51 shirts one day.
This means that 
All short-sleeved shirts cost $14.00 each and all long-sleeved shirts cost $23.00 each. Total receipts for the day were $921.00.
This means that

How many of each kind of shirt were sold?
We have to solve the system of equations.


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28 short-sleeved shirts were sold and 23 long-sleeved shirts were sold.