# When I was 4 years old, my sister was half my age. Now am 100. How old is my sister?

If your sister was half your age when you were 4 years old, she was 2 years old, meaning that she is 2 years younger than you and thus 98 when you are 100.

You can make use of equations.

For instance, let the number of years you need to grow to become 100 years old be x. Then

4 + x = 100

x = 100 - 4 = 96

When you are 4 years old, your sister is half your age, that is, 0.5 x 4 = 2 years old.

Your sister grows for 96 years to become 2 + 96 = 98 years, when you are 100 years old.

Approved by eNotes Editorial Team

Your sister is 2 years younger than you as when you are 4 she is 2(half  your age); therefore when you are 100 your sister is 98 years old.

Approved by eNotes Editorial Team

When you were 4 years old, your sister was half your age. Half of 4 is 2, your sister was 2 years old when you were 4 years old or she is 2 years younger to you.

Your present age is 100, as your sister is 2 years younger to you, she is 98 years old.

Approved by eNotes Editorial Team