Question

The temperature in the late afternoon

was -7.5°C. It dropped 5 degrees by early
evening and then dropped 8.5 degrees by midnight. Write an equation to express the total change in temperature that day.

Answer 1

-7.5 - (8.5 + 5)

Explanation:

We just add together the values of how much it dropped at different parts of the day, and subtract them from what we started with. The parenthesis are important cause we want to know what the total temperature drop for the day was before we subtract it to get the actual temperature we end up with.

Answer 2

T= - 5°C - 8.5°C = -13.5°C

Explanation:

The initial temperature in the late afternoon was -7.5°C.

It dropped 5 degrees by early evening and then dropped 8.5 degrees by midnight.

Change in temperature (in evening) = -5°C

Change in temperature (in midnight) = -8.5°C

Here negative sign represents the decrease in the temperature.

Let T be the total change in the temperature.

So, total change in the temperature is

T = - 5°C - 8.5°C

T = 13.5°C

Therefore, the required equation is T = - 5°C - 8.5°C = 13.5°C.