A bird sanctuary initially contains 1000 birds. Each year, 10% of the birds fly away, so the sanctuary is restocked with 40 new birds. Write a recursive rule for the number an of birds at the start of the nth year.

At the "no mutants allowed" country farm, every sheep has 4 legs, every chicken has two legs, and all animals have only 1 head. asked to count how many sheep and chicken are in the fields, a farm boy reports back that there are 140 feet and 50 heads. how many sheep and chicken are there? there are sheep and chicken at the farm.