Less Searching. More Learning.

QUESTRA — Engineering Formula Quick Sheet

Original introductory resource

Continuity (steady incompressible flow): A1 v1 = A2 v2
Reynolds number: Re = rho v D / mu
Plane-wall heat conduction: Q = k A (T1-T2) / L
Ideal gas: P V = n R T
Ohm law: V = I R
Power (electrical DC): P = V I
Normal stress: sigma = F / A

Use consistent SI units. Check the assumptions before applying each formula.

QUESTRA — Quantitative Aptitude Revision Notes

Percentage change = (new - old) / old x 100
Average = sum of values / number of values
Simple interest = principal x rate x time / 100
Work rate = 1 / time taken
Combined work rate = sum of individual work rates
Speed = distance / time

Example: 25 percent of 240 = 60.
Example: A 10-day worker and a 15-day worker together take 6 days.