6. 40 minutes (15/3 = 5 minutes/mile) - 5*8 = 40 min
7. 15,840 ft / 5 = 3.168 ft
21/8 miles per hour. Or 2 and 5/8 miles per hour
(a) Volume of any Pyramid = 
cubic units
(b) Sarah doesn't have to go through all the hard work as the smaller pyramid has a ratio of 2:3 to the bigger pyramid, so we get the equation, to help us solve it.
Hope that helps!
0.2(x + 20) - 3 > -7 - 6.2x.....distribute trhr the parenthesis
0.2x + 4 - 3 > -7 - 6.2x...simplify
0.2x + 1 > - 7 - 6.2x...addition property...add 6.2x to both sides
0.2x + 6.2x + 1 > -7 ...simplify
6.4x + 1 > - 7.....subtraction property....subtract 1 from both sides
6.4x > -7 - 1....simplify
6.4x > -8....division property....divide both sides by 6.4
x > -8 / 6.4...simplify
x > - 1.25 <==
