A certain kind of animal weighs about 73 pounds at birth and gains about 2 pounds per day for the first few weeks. Determine those days for which the animal's weighs more than 121 pounds.

The animal's weight is more than 121 pounds when the animal is more than__ days old.

2 answers

You have an arithmetic sequence with
a = 73 , and d = 2

term(n) = a + (n-1)d
so solve
73 + 3(n-1) >121
24