Question

An object falls 9 meters during the first second, another 27 meters during the second second, and then 81 meters more during the third second. If this pattern continues, how far does the object fall during the first 4 seconds?
Hint: cap s sub n equals start fraction a sub one left parenthesis one minus r to the power of n end power right parenthesis over one minus r end fraction comma r ≠ 1, where a1 is the first term and r is the common ratio.

117 meters
360 meters
426 meters
980 meters

Answer 1

360 meters is the answer as 9 meter in 1st second ,27 meter in 2nd and 81 in 3rd it is in a series of geometric progression ...of 9,27,81 in which 9*3 =27,27*3=81 so next number will be 81*3=243 total distance moved in 4 seconds is 243+81+27+9=360 meters