Shortcut Trick
Trick = (Increase% x 100) ÷ (100 + Increase%)
⇒ (33 x 100) ÷ (100 + 33)
⇒ 13333×100 = 24.8%
∴ Required % is 24.8%.
Alternate Method - 1Given:
Price of sugar rises = 33%.
Concept used:
Selling price at profit = Cost price x (100 + profit%)/100
Calculation:
Let initial price of sugar = 100
⇒ Initial consumption = 100
⇒ Total expenditure = price x consumption
⇒ 100 x 100 = 10000
Now new price of sugar after increase of 33% = 100 + 33 = 133
But new expenditure is remain same = 10000
⇒ New consumption = expenditure ÷ new price
⇒ New consumption = 10000/133
⇒ % Decrease in consumption = 100 - 10000/133 = 3300/133
∴ % Decrease in consumption is 24.8.
Alternate Method - 2 Given:
Price of sugar rises = 33%.
Concept used:
Selling price at profit = Cost price x (100 + profit%)/100
Calculation:
Let initial price of sugar = Rs, A
⇒ Initial consumption = B
⇒ Total expenditure = price x consumption
⇒ Total expenditure = A x B = AB
Now new price of sugar after increase of 33% = A x (100 + 33) /100
⇒ 133A/100
⇒ New expenditure is remain same = AB
⇒ New consumption = expenditure ÷ new price
⇒ New consumption = 133AAB×100 = 100B/133
⇒ Decrease in consumption = B - 100B/133
⇒ 33B/133
⇒ % Decrease in consumption = 133×B33B×100 = 24.8
∴ % Decrease in consumption is 24.8.
Important PointsProfit = Selling price - Cost price
Profit% = [(Selling price - Cost price) × 100] ÷ Cost price
Selling price at profit = Cost price x (100 + profit%)/100
Loss = Cost price - Selling price
Loss% = [(Cost price - Selling price) × 100] ÷ Cost price
Selling price at loss = Cost price x (100 - loss%)/100
Selling price at discount = Cost price x (100 - discount%)/100