SAT Practice Exam

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Scientific Notation

If 15.7 = 1570 x 10^t, what is the value of t?

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Answer
Problems like this involve decimal shifting. Since 15.7 is less than 1570, we need to shift our decimal place to the left

Decimal Shift Step 1

Shifting the decimal place 1 place(s) to the left, we get 157

Decimal Shift Step 2

Shifting the decimal place 2 place(s) to the left, we get 15.7

Shifting the decimal place left signifies a negative power, so our answer is t = -1 x 2 = -2

Writing this out in scientific formation using our answer, we get

15.7 = 1570 x 10^-2