Megan drove from her house to work at an average speed of 45 miles per hour. the drive took her 20 minutes. if the drive home took her 30 minutes and she used the same route in reverse, what was her average speed going home? question 10 options: 30 miles per hour 13.33 miles per hour 26.6 miles per hour 3 miles per hour find the lcm of the set of polynomials. 3a3c, 6b4, b2c2 question 20 options: 18a3b4c3 18a2b4c2 18a3b4c2 18a3b3c2

30 miles per hour.

Step-by-step explanation:

First work out the distance from home to work:

Speed = distance / time

45 = d / 1/3           ( Note:  20 minutes =  1/3 of an hour).

d = 1/3 * 45

=  15 miles.

Driving back home:

Speed = 15 / 1/2

= 30 mph (answer).

LCM of  3a^3c, 6b^4, b^2c^2:

LCM of 3 and 6 is 6

of a^3 is a^3

of b^2, b^4 is b^4

and of c and c^2 is c^2.

So the answer is:

= 6a^3b^4c^2

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)