Josiah has a mass of 75 kg and wants to know how many helium-filled balloons it would take to fly. The density of helium is about 1 kg / m^3 less than regular air, which means a cubic meter of helium can lift about 1 kg. Fully inflated, a balloon has a diameter of 0.3 m and can be modeled as a sphere. He neglects the mass of the balloon in his calculations. About how many balloons would it take to lift Josiah

-13

step-by-step explanation:

f(x)=2x-5 for f(-4)

f(-4)   means let x=-4

f(-4) = 2(-4) -5

f(-4) =-8-5

      = -13

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.

c

step-by-step explanation:

step-by-step explanation: