I don't think I am understanding this question.
A zoo started with 16 cranes and panned to hatch 20 chicks. A few birds were kept for breeding and the rest realeased into the wild. At the end of last year, a total of 136 cranes had spent some time in the zoo. If the pattern continues, how many cranes will there be by the end of this year? the next year?
I don't know how many cranes they kept so I called that 'x'
I know they hatch 20 cranes a year so the number of years it took to get to 136 cranes would be 136/20 = 6.8 years
So by the end of the year would be 7 years so 20 x 7 = 140 cranes
So by the end of next year would be 140 + 20 = 160
planned to hatch 20 chicks a year* CORRECTIONposted by Lena
The equation would actually be 16+(n-1)(20) because they initially started off with 16 cranes so 16=a and they increase every year by 20 cranes so d=20 so plug the values into a+(n-1)d. There would be 156 cranes at the end of this year and 176 by the next year.posted by Yasmeen