Percent Increase and Decrease: Additional Practice (Set 2)

Apply the changes one at a time. The increase gives $1.20 \times 100 = 120$. The decrease is then taken of $120$, not of $100$.

$0.80 \times 120 = 96$

The final price is $96$ dollars, not $100$, because the $20\%$ drop is figured on the larger $120$.

The change is $15 - 12 = 3$. Compare it to the original $12$.

$\frac{3}{12} \times 100\% = 0.25 \times 100\% = 25\%$

So the price rose by $25\%$.

Apply the changes in order. The decrease gives $0.70 \times 200 = 140$, and the increase is then taken of $140$.

$1.30 \times 140 = 182$

The final value is $182$, below the original $200$, because the $30\%$ rise is figured on the smaller $140$.

Apply the changes in order, each on the previous amount. The first gives $1.10 \times 500 = 550$, then the second is taken of $550$.

$1.20 \times 550 = 660$

The final value is $660$. Adding the percents to $30\%$ would wrongly give $650$, because the second change is on the larger $550$.

A $40\%$ increase makes the new value $140\%$ of the original, so divide by $1.40$.

$\frac{7}{1.40} = 5$

So the original quantity was $5$. Check: $1.40 \times 5 = 7$.

A $35\%$ increase uses the multiplier $1 + 0.35 = 1.35$.

$1.35 \times 480 = 648$

So the new value is $648$.

The first discount gives $0.90 \times 200 = 180$. The coupon then takes $10\%$ off that reduced $180$.

$0.90 \times 180 = 162$

The final price is $162$ dollars, not $160$, because the two $10\%$ cuts act on different amounts (so they do not add to $20\%$).

An $18\%$ tip is added, so multiply by $1 + 0.18 = 1.18$.

$1.18 \times 90 = 106.20$

The total is $106.20$ dollars.

A $25\%$ markup makes the price $125\%$ of the cost, so the cost is the price divided by $1.25$.

$\frac{35}{1.25} = 28$

The shirt cost the store $28$ dollars. Check: $1.25 \times 28 = 35$.

The change is $29 - 25 = 4$. Compare it to the original $25$.

$\frac{4}{25} \times 100\% = 0.16 \times 100\% = 16\%$

So the price rose by $16\%$.

The change is $1{,}500 - 1{,}200 = 300$. Compare it to the original $1{,}200$.

$\frac{300}{1{,}200} \times 100\% = 0.25 \times 100\% = 25\%$

So the collection grew by $25\%$.

First the discount: $0.60 \times 150 = 90$ is the sale price. Then tax adds $6\%$ to that $90$.

$1.06 \times 90 = 95.40$

The final cost is $95.40$ dollars.