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GB-14-03-001 · Reverse percentage

After a discount of 22%, a desk costs £1107.60. Work out its price before the discount.

Reverse Percentages Booklet p. 53
Method
1) Call Original Amount x
2) Write x × ((100 − %) /
1
0
0) = New Amount
3) Divide both sides by the decimal multiplier
Worked Example (GB-14-03-001)
Booklet p. 53 (Reverse %): Call Original x  ⇒  x×(100±%100)=New Amount\mathbf{x} \;\Rightarrow\; \mathbf{x \times \left(\frac{100 \pm \%}{100}\right) = \text{New Amount}} (Divide both sides by multiplier!)
1) The sale price is 78% of the original.
2) Divide £1107.60 by 0.78.
3) £1420.00
£1420.00