Algebra Readiness Chapter 4 Section 5

4.5: Divide Integers The mean, also called the average, is the sum of the numbers in a set of data divided by the number of items in the set. The average rate of change of one quantity with respect to another is the change of the first quantity divided by the change in the second quantity.

Dividing Integers * The quotient of two integers with the same sign is positive. * The quotient of two integers with different signs is negative. * The quotient of 0 and any nonzero integer is 0.

Dividing Integers Example 1 a – – = 3 Same sign, so quotient is positive. b – = Different signs, so quotient is negative. 7 – c – = Different signs, so quotient is negative. 5 – d – = The quotient of zero and any nonzero integer is 0. 0

Finding a Mean Example 2 Find the mean of the numbers: 21, –53, –46, 32, –14. = Write sum divided by 5. 5 Mean 21 + (– 53 ) + (– 46 ) (– 14 ) = Divide. – 12 = Add. 5 – 60 ANSWER The mean of the numbers is 12. –

Find the quotient. 1. – 1 ANSWER 58 – ANSWER – 19 ANSWER – – 3. – 6 72 ANSWER – Practice for Examples 1 and 2

Find the mean of the numbers , –26, –25, 46, –55 ANSWER –7 ANSWER 2 6. –3, 0, 4, 5, –2, 8 Practice for Examples 1 and 2

Finding the Mean of Data Example 3 The table shows the average monthly high temperature for the coldest months in Barrow, Alaska. What is the mean high temperature for these months? = – 3 = 6 – 18 = 6 Mean 5 + (– 5 ) + (– 7 ) + (– 10 ) SOLUTION + (– 7 ) + 6 ANSWER The mean high temperature is 3°F. – MonthTemp. ( ° F) November December January February March April – – – –

7.At McMurdo Base in Antarctica, the average monthly temperatures for January through April are 27°F, 16°F, 1°F, and –4°F. What is the mean average temperature for those months? ANSWER 10°F Practice for Example 3

Finding the Average Rate of Change Example 4 A hot air balloon flying at an altitude of 1500 feet descended to an altitude of 616 feet in 34 minutes. What was the average rate of change in altitude in feet per minute? To find the change in altitude, subtract the starting altitude from the ending altitude. SOLUTION = – – 1500 Divide by the time it took the balloon to descend to find the rate of change. 34 min – 884 ft = – 26 ft/min

8.A scuba diver swimming at an elevation of –105 feet relative to the surface of the water rises to an elevation of –15 feet in 3 minutes. What is the average rate of change in the diver’s elevation in feet per minute? ANSWER 30 ft/min Practice for Example 4