Answer:
The radius of the circles are
and 
Step-by-step explanation:
Let
x-----> the radius of larger circle
y----> the radius of smaller circle
we know that

-----> equation A
Remember that
-----> equation B
substitute equation B in equation A and solve for y





Find the value of x


therefore
The radius of the circles are
and 
Surface area= 2(6x15)+2(7x15)+2(6x7)
=180+210+84
=474m
Volume=15x6x7
=630m^2
It’s 6.72 you add the two numbers
A) multiple the 3 x 4 and add 1.
3 x 4 = 12 + 1 = 13
13/3
B) (7 x 3) + 2 = 23/3
C) (4 x 2) + 1 = 9/2
D) (2 x 8) + 7 = 23/8
Let b and s be the velocity of the boat and stream respectively....
3(b-s)=27
b-s=9
b=9+s we will use this in the second equation....
2(b+s)=30
b+s=15, now use b found above in this to get:
9+s+s=15
2s+9=15
2s=6
s=3, and since from earlier b-s=9, b=9+s so
b=12
So the speed of the boat is 12mph and the stream is 3 mph