This is an exponential growth problem. Exponential growth can be expressed mathematically in the following way:

.
Parameter a presents initial amount.
Parameter r is percentage increase.
Parameter t is time.
An equation that would describe given problem is:

t is the time in years.
I attached the graph of this function.
After solving I have come up with 6 2/9 or 6.22222.
81,149, 274.... adding three numbers from the last would help you
like if you take 7 = 4 + 2 +1
or 13 = 7 + 4 +2
similarly 44+24+13 = 81
81+44 +24 = 149
149 + 81 +44 = 274
hope you get it!
Answer:
$54
Step-by-step explanation:
she had 6 grandchildren and she used $9 for one grandchild so we multiply
9 x 6 = $ 54