905SPMath2012

Textbook: Page 70, Question 23

23 a) Write a subtraction statement involving two negative fractions or negative mixed numbers so that the difference is -4/3 (negative four thirds).

23 b) Share your statement with a classmate.

That would be you.

Textbook: Page 60, Question 13

A submarine was cruising at a depth of 153m. It then rose at 4.5m/min for 15 min.
   a) What was the submarine's depth at the end of this rise?
   b) If the submarine continues to rise at the same rate, how much longer will it take to reach the surface?

                                               A) 85.5m

B) It would take 19 minutes for the submarine to reach the surface

TextBook Page 62 Question 23

One week in October in Iqaluit, Nunavut, the daily high temperatures were -4.6°C, -0.5°C, 1.2°C, 2.3°C, -1.1°C, 1.5°C, and -3.0°C. What was the mean daily high temperature that week?

To find the mean you first add every number.

-4.6+-0.5+1.2+2.3+-1.1+1.5+-3.0

Then you just simply divide the numbers to the amount of number there is.

(-4.6+-0.5+1.2+2.3+-1.1+1.5+-3.0) ÷ 7 = -0.6

Or you can Just simply do this -4.2÷7= -0.6
-4.2 is the sum of all the numbers.

Textbook: page 61. Question 15

15. In dry air, the temperature decreases by about 0.65°C for each 100 metre increase in altitude.

a) The temperature in Red Deer, Alberta, is 10°C on a dry day. What is the temperature outside an aircraft 2.8 km above the city?

The number became 2800 because I converted 2.8 km to metres, so it became 2800. I multiplied it by .65 because the answer determines what to add or subtract it to the current temperature. I divided 1820 to 100 because it would easier to subtract the number to the temperature. I put 10 first because you are subtracting from 10. The temperature outside of the aircraft is -8.20°C.

b) The temperature outside an aircraft 1600 metres above Red Deer is -8.5°C. Whats is the temperature in the city.

I multiplied it by .65 because the answer determines what to add or subtract from the temperature. I divided 1040 by 100 because it would be easier to subtract the number to the temperature. The temperature in Red Deer is -1.9°C.

Textbook Page 61 Question 19

19.) A company made a profit of $8.6 million in its first year. It lost $5.9 million in its second year and lost another $6.3 million in its third year.

A.) What was the average profit or loss per year over the first three years?

The company has the average loss of $1.2 million per year over the first three years.

How much money they had:

Year 1= $8.6 million
Year 2= $2.7 million
Year 3= -$3.6 million
-$3.6 million divided by 3 (number of years) = -$1.2 million dollars.

B.) The company broke even the first four years. What was its profit or loss in the fourth year?

The company made the profit of $3.6 million.

By the end of the third year the company had the debt of $3.6 million and in order for them to get that money back they will have to make the profit of $3.6 million.