Answer:
Amy is (21.6 - 14.4) 7.2 km/hr faster than Bill.
Distance = speed / time
Amy's speed
40 minutes = 40/60 = 2/3 hours
14.4 = speed / 2/3
Speed = 14.4 * 3/2 = 21.6 km/ hr
Bill speed
60 minutes = 1 hour
Speed = 14.4 km / hr.
Answer: c
Step-by-step explanation:
Remark
A cube has six sides, all of them equal. The formula for 1 side is s^2. The formula for all six = 6s^2.
Step One
Find the surface area of the larger cube.
Area = 6 *s^2
s = 15
Area = 6 *15^2
Area = 6 * 225
Area = 1350
Step Two
Find the area of the smaller cube
Area = 6s^2
Area = 6 * 12^2
Area = 6 * 144
Area = 864
Step Three
Find the difference
Area1 - Area2 = difference
1350 - 864 = 486
The difference is area = 486 units^2 <<<<< Answer
There is a slightly shorter way. Take out the common factor of 6
Difference = 6 * (15^2 - 12^2)
Difference = 6 * (225 - 144)
Difference = 6 * (81)
Difference = 486
your answer would be -25.078
i hope this helps.!
