📊 Averages
Average = Sum of terms / Number of terms
Weighted Average = (w1x1 + w2x2)/(w1+w2)
📈 Percentages
x% of y = (x×y)/100
Increase = New - Original
% Increase = (Increase/Original)×100
💰 Profit & Loss
Profit = SP - CP
Loss = CP - SP
Profit% = (Profit/CP)×100
⏰ Time & Work
Work = Rate × Time
1 day work = 1/Total days
Combined work = 1/A + 1/B
🚗 Speed & Distance
Speed = Distance/Time
Avg Speed = Total Distance/Total Time
Relative Speed = S1 + S2 (opposite)
💵 Simple Interest
SI = (P×R×T)/100
Amount = P + SI
P = Principal, R = Rate, T = Time
📈 Compound Interest
CI = P(1+R/100)^T - P
Amount = P(1+R/100)^T
Half-yearly: R/2, T×2
🔢 Ratio & Proportion
a:b = c:d → ad = bc
Duplicate = a²:b²
Triplicate = a³:b³