Question

Gold has a density of 19.3 g/cm^3. Current price is $1192 per troy ounce. What is the value of a cube of gold iwth a side length of 1.00 inch?

1 troy ounce = 31.1 g

2.52 cm = 1 inch

a) $3.77 x 10^4

b) $1.21 x 10^4

c) $8.52 x 10^4

d) $5.86 x 10^4

e) $1.57 x 10^5

why is the answer B? Thank you!

Answer 1

cube volume = 1 x 1 x 1 = 1 inch^3

1 inch = 2.52 cm

1 inch^3 = (2.52 )^3 cm^3

              = 16 cm^3

density = mass / volume

mass = density x volume = 19.3 x 16 = 308.8 g

1 troy ounce = 31.1 g

x troy ounce = 308.8 g

x = 308.8 /31.1 = 9.93 troy ounce

so finally mass = 9.93 troy ounce

for 1 troy ounce ------------------> $1192

    9.93 troy ounce -------------> ?????

cost = 1192 x 9.93 / 1 = 1.2 x 10^4

     which mathces to your answer $1.21 x 10^4