Respuesta :
Her brother is 7 years old at the moment. He will be 21 when his sister is 36.
I hope this helps you
brothers age 3.?=21 ?=7
when girl 36
now she is 21
36=21+15 it's have to past 15 years
15 years later brothers age
7+15=22
brothers age 3.?=21 ?=7
when girl 36
now she is 21
36=21+15 it's have to past 15 years
15 years later brothers age
7+15=22