
Change x to y, and y to x.

solve for y:

Your answer is:

Well it shows that the main cube is 9 blocks tall. It is a perfect cube, not a rectangular prism or anything, so every side is the same. So 9 cubed. Or, in other words, 9*9*9
Answer:
131.3 miles
Step-by-step explanation:
The two cars are moving from different directions. The total distance between the two cars = 118 miles + 256 miles = 374 miles.
Let us assume that the two cars meet at point O, let the distance between car c and O be d₁, the distance between car d and point O be d₂, hence:
d₁ + d₂ = 374 miles (1)
Let speed of car d be x mph, therefore speed of car c = 2x mph (twice of car d). If it take the cars t hours to meet at the same point, hence
For car c:
2x = d₁/t
t = d₁ / 2x
For car d;
x = d₂/t
t = d₂/ x
Since it takes both cars the same time to meet at the same point, therefore:
d₁/2x = d₂ / x
d₁ = 2d₂
d₁ - 2d₂ = 0 (2)
Solving equation 1 and 2 simultaneously gives d₁ = 249.3 miles, d₂ = 124.7 miles
Therefore the distance from point of meet to Boston = 249.3 - 118 = 131.3 miles
₇P₅ is a permutation. you can find this setting in the statistics menu of your scientific calculator (i think).
If you don't have a scientific calculator, you can use the following formula:
nPr = 
₇P₅ = 
= 
= 
= 7 * 6 * 5 * 4 * 3
= 2520
Answer: C