Question

The temperature was 78°F at 3 P.M. Each hour for

Answer 1

Answer:

  66 °F

Step-by-step explanation:

At 4 P.M., the temperature had decreased by 3° from the temperature at 3 P.M., so was ...

  4 P.M. temp = 78 °F -3° = 75 °F

This was repeated until 7 P.M.

  5 P.M. temp = 75 °F -3° = 72 °F

  6 P.M. temp = 72 °F -3° = 69 °F

  7 P.M. temp = 69 °F -3° = 66 °F

The temperature at 7 P.M. was 66 °F.

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Of course the repeated subtraction can be simplified using multiplication. The subtraction of 3° four times is equivalent to the subtraction of . . .

  (3°)(4) = 12°

That is, the temperature at 7 P.M. is ...

  78 °F -3°×4 = 78 °F -12° = 66 °F