Answer:
(2,5)
or x=2, y=5
Step-by-step explanation:
3x+2y=16
substitute y =x+3 every place you see a y
3x + 2(x+3) = 16
distribute
3x + 2x +6 = 16
combine like terms
5x+6 = 16
subtract 6 from each side
5x+6 -6 =16-6
5x =10
divide by 5
5x/5 = 10/5
x = 2
now we need to find y
y = x+3
y = 2+3
y=5
(2,5)
or x=2, y=5
The rate at which the sand is leaking, is the same rate at which the volume of the cone is increasing, so the rate of the sand leak is then the same as dv/dt of the cone.
now, we know the height is always the same length as the radius, thus h = r.
4 x 300 = 1,200
4 x 60 = 240
4 x 2 = 8
_1,200
_ _240
+ _ _ 8
_______
_1,448
So 4 x 362 = 1,448
Double check:
1,000 / 4 = 250
400 / 4 = 100
40 / 4 = 10
8 / 4 = 2
_250
_100
__10
+__2
_____
_362
So 1,448 / 4 = 362, which is correct.
3 packages though she'll have extra left over because 7+7=14 that will only be 2 packages but since she needs 15 she'll have to buy 3 packages