Calculate the percentage decrease, percentage increase or decrease, or the new value after an increase or decrease for each problem.

Steps to Solve

1. 2(a): Calculate the percentage decrease

To find the percentage decrease, divide the amount of the decrease by the original amount, then multiply by 100. $Percentage\ Decrease = \frac{Decrease}{Original\ Amount} \times 100$ In this case, the decrease is 6 and the original amount is 30. $Percentage\ Decrease = \frac{6}{30} \times 100 = 0.2 \times 100 = 20$%

2. 2(b): Calculate the percentage decrease

The original amount is 25 and the new amount is 18. The decrease is $25 - 18 = 7$. $Percentage\ Decrease = \frac{7}{25} \times 100 = 0.28 \times 100 = 28$%

3. 2(c): Calculate the percentage decrease

The decrease is 15 m and the original amount is 60 m. $Percentage\ Decrease = \frac{15}{60} \times 100 = 0.25 \times 100 = 25$%

4. 2(d): Calculate the percentage decrease

The original amount is 56 kg, and the new amount is 14 kg. The decrease is $56 - 14 = 42$ kg. $Percentage\ Decrease = \frac{42}{56} \times 100 = 0.75 \times 100 = 75$%

5. 3(a): Calculate the increase

To increase 50 by 16%, we multiply 50 by 16% (or 0.16) to find the amount of the increase. $Increase = 50 \times 0.16 = 8$

6. 3(b): Calculate the decrease

To decrease 48 by 25%, we multiply 48 by 25% (or 0.25) to find the amount of the decrease. $Decrease = 48 \times 0.25 = 12$

7. 3(c): Calculate the increase

To increase 70 $m^2$ by 150%, we multiply 70 by 150% (or 1.50) to find the amount of the increase. $Increase = 70 \times 1.50 = 105\ m^2$

8. 3(d): Calculate the decrease

To decrease 80°C by 15%, we multiply 80 by 15% (or 0.15) to find the amount of the decrease. $Decrease = 80 \times 0.15 = 12\ °C$

9. 4(a): Calculate the new value

To increase 75 by 8%, first calculate the increase: $75 \times 0.08 = 6$. Then add this to the original value: $75 + 6 = 81$. $New\ Value = 81$

10. 4(b): Calculate the new value

To decrease 300 by 12%, first calculate the decrease: $300 \times 0.12 = 36$. Then subtract this from the original value: $300 - 36 = 264$. $New\ Value = 264$

11. 4(c): Calculate the new value

To increase 125 hours by 32%, first calculate the increase: $125 \times 0.32 = 40$. Then add this to the original value: $125 + 40 = 165$. $New\ Value = 165\ hours$

12. 4(d): Calculate the new value

To decrease 168 mL by 75%, first calculate the decrease: $168 \times 0.75 = 126$. Then subtract this from the original value: $168 - 126 = 42$. $New\ Value = 42\ mL$