John is 3 times as old as susan. Mark is 5 years younger than john the sum of their ages is 30. how old is susan

Susan is 5 years old

Step-by-step explanation:

Make a system of equations based on the info:

J=3S

M=J-5

J+M+S=30

Since we have the value of J, plug it in to either equation:

M=3S-5

Same deal with M:

3S+3S-5+S=30

7S-5=30

7S=35

S=5

So Susan is 5 years old

80π/3 or about 83.775

step-by-step explanation:

since a cone is 1/3 of a cylinder, we need to find the base's area. since area = πr^2, we get 16π. then, multiplying this by 5, we get 80π. dividing by 3, since the cone's volume is 1/3 of that of a cylinder's, we get 80π/3.

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choose (5, 1.5) and (-1.5,-3.5)

step-by-step explanation:

5 - 1.5 =3.5

-1.5 - (-3.5) = 2

3.5 + 2 =5.5

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