2020 · Q90
If p, q, r, s and t represent length, breadth, height, surface area and volume of a cuboid respectively, then what is 1/p + 1/q + 1/r equal to?
Elementary MathematicsMensuration
- As/t
- B2t/s
- Cs/2t
- D2s/t
Explanation
1/p+1/q+1/r = (pq+qr+rp)/pqr = (s/2)/t = s/(2t). Hence option (C). Indeed pq+qr+rp = s/2 by the surface-area formula, and pqr = t.