SOLUTION: What term in the sequence (1.6,1.2,0.8,0.4,...) is -38.4 ? I guessed 99 but was marked wrong . I don't know how to do this , please help me :)

Question 118654: What term in the sequence (1.6,1.2,0.8,0.4,...) is -38.4 ? I guessed 99 but was marked wrong . I don't know how to do this , please help me :)
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Look at the terms and see if you can determine the pattern.
First term = 1.6
Second term = 1.6-0.4 = 1.2
Third term = 1.6-0.4-0.4 = 0.8
Fourth term = 1.6-0.4-0.4-0.4 = 0.4
I think you can see the pattern.
Nth term = 1.6 - 0.4*(N-1)
Now that you have the formula, set it equal to the number to find N.

Subtract 1.6 from both sides of the equation.
Divide both sides by 0.4.

Check your answer with your original formula.
101st term = 1.6 - 0.4(101-1)=1.6-40.0=-38.4.
The answer checks out.
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