subtracting a negative number is the same as

a: adding a positive number
b: subtracting a positive number
c: subtracting a negative number
d: adding a negative number

Kate is 3 years old

Explanation:

Kate is x for example, then her father would be

x+32

In five years he would be x+32+5, x+37, but he would also be 5 times older.

Kate will also be x+5.

SO, we know that

x+37=5 · (x+5)

When we simplify, we get

x+37 = 5x+25

Simplify further, you get

12=4x, so

3=x

Kate is 3 years old currently