In an experiment, quantities a, b and c are measured with percentage errors of ±1%, ±3% and ±2% respectively. The quantity Q is calculated using the expression Q=ab2c3. The percentage error in Q is

Power of a is 1, its contribution to percent error in Q is 1×1% = 1%. Similarly the power of b is 2, its contribution to percent error in Q is 2×3% = 6%. Finally power of C is -3, its contribution to percent error in X is −3 ×2% = 6%. Add all these