Section 10 - Exponents and Exponential Functions (Edition 2)

---

Category 48 Example 1 - mental math

Only in answer choice B n increases 3 times with every 0.5 increase of m. In all other answer choices the increase is same each time.

---

Category 49 Example 1 - mental math

Since the exponential decrease is by 7% during each time interval, x = 0.93. Since the decrease is every 3 years, in 15 years there will be 5 decreases. Hence, t = 5. Match the values of x and t with the answer choices.

Category 49 Example 2 Question 1 - mental math

Since the increase is by 2% each year than the preceding year, x = 1.02. Match it with the answer choices.

Section 9 - Percent (Edition 2)

---

Category 43 Example 3 - mental math

The two discounts as decimal are 0.86 and 0.77. Multiplying them with the original price will give the discounted price.

---

Category 44 Example 1 Question 1 - mental math

The discount = decrease as decimal is 0.85 and sales tax = increase = 1.06. Dividing them with the final price will give the original price.

Section 8 - Ratio, Proportion, and Rate (Edition 2)

---

Category 41 Example 1 - mental math

The number of students in the karate team are 60 - 24 = 36. The ratio of 24:36 = 2:3.

Category 41 Example 4 - mental math

Since 9 centimeters is 45 times of 0.2 centimeters, the corresponding feet will also be 45 times: 10 x 45 = 450.

---

Category 42 Example 2 - mental math

Taxi A: Since 15 minutes is one-fourth of 60 minutes (1 hour), miles will also be one-fourth = 40/4 = 10.

Taxi B: Since 15 minutes is one-fourth of 60 minutes (1 hour), miles will also be one-fourth = 30/4 = 7.5.

Distance = 10 + 7.5 = 17.5.