Question

Distance between two parallel planes $2x+y+2z=8$ and $4x+2y+4z+5=0$ is

• A. $\frac{5}{2}$
• B. $\frac{7}{2}$
• C. $\frac{9}{2}$
• D. $\frac{3}{2}$

Answer 1

Answer: (B)

The planes are $4x+2y+4z=16,4x+2y+4z=-5$
Distance between planes = $\frac{16-\left(-5\right)}{\sqrt{4^2+2^2+4^2}}=\frac{21}{6}=\frac{7}{2}$