<span>B.) between 6 an 6.5
</span>
Total cost, C = 8x^2 + 12xz
volume, V = (x^2)*z = 10
C = 8x^2 + 12x*10/x^2
= 8x^2 + 120/x
dC/dx = 16x - 120/x^2 = 0
16x = 120/x^2
x^3 = 120/16
x = 1.957 ft
d^2C/dx^2 = 16 +240/x^3 = +ve for x = 1.957
so, C is minimum when
x = 1.957 ft z = 2.61 ft
Length of the base x is 1.957 ft and height of side z is 2.61 ft
The lengths of P,Q, and R are 6 ft 9 in, 11 ft 3 in and 15 ft 9
Answer:
x = number of bicycles = 35
y = number of cars = 55
Step-by-step explanation:
Let
x = number of bicycles
y = number of cars
x + y = 80 (1)
2x + 4y = 270 (2)
From (1)
x = 80 - y
Substitute x = 80 - y into (2)
2x + 4y = 270 (2)
2(80 - y) + 4y = 270
160 - 2y + 4y = 270
- 2y + 4y = 270 - 160
2y = 110
y = 110/2
y = 55
Substitute y = 55 into (1)
x + y = 80 (1)
x + 55 = 80
x = 80 - 55
x = 35
x = number of bicycles = 35
y = number of cars = 55
37 is halfway between 23 and 51