A sequence is defined by the recursive formula f(n + 1) = 1.5f(n). Which sequence could be generated using the formula?

–12, –18, –27, ...
–20, 30, –45, ...
–18, –16.5, –15, ...
–16, –17.5, –19, ...

Question

A sequence is defined by the recursive formula f(n + 1) = 1.5f(n). Which sequence could be generated using the formula?

–12, –18, –27, ...
–20, 30, –45, ...
–18, –16.5, –15, ...
–16, –17.5, –19, ...

Mercury · Answer

f(n + 1) = 1.5f(n)
this specifies that each term in a sequence is obtained by multiplying the previous term by 1.5

so, let's start with the first choice and see if it could be generated w/ the formula
first term: –12
next term that would be generated by the formula is -12*1.5 = -18. so far so good. but it needs to work for the entire sequence. so check what the next term would be. if it's -27, then A is your solution; if not, keep trying with the other choices