18. What is the change in temperature between −20°F and 30°F?(1 point)
-10 °F
10 °F
50 °F
-50 °F
The change in temperature between −20°F and 30°F is 50 °F.
19. The temperature was −5°F this morning. If the temperature dropped 8°F, what is the temperature now?(1 point)
-13 °F
3 °F
-3 °F
13 °F
The temperature now, after dropping 8°F from −5°F, is -13°F.
20. A Navy submarine is 650 feet below sea level. If it ascends 200 feet, which integer represents its new position?(1 point)
-850
450
850
-450
If a submarine that is 650 feet below sea level ascends 200 feet, its new position would be 450 feet below sea level. Therefore, the integer that represents its new position is -450.
21. John threw a rock into a lake from a bridge 124 feet above the river's surface. The rock sinks 81 feet below the river’s surface. What is the distance between the elevations? (Hint: Draw a picture or use a number line.)(1 point)
43 feet
205 feet
-205 feet
-43 feet
The distance between John's position on the bridge (124 feet above the river's surface) and the rock's position below the river's surface (81 feet) is 205 feet. Therefore, the distance between the elevations is 205 feet.
22. Find the sum of -12 and -36.(1 point)
24
-48
48
-24
The sum of -12 and -36 is -48.
To find the change in temperature between -20°F and 30°F, you need to subtract the initial temperature from the final temperature.
In this case, you subtract -20°F from 30°F:
30°F - (-20°F) = 30°F + 20°F = 50°F
Therefore, the change in temperature between -20°F and 30°F is 50°F.
So the correct answer is 50 °F.