In three years' time a pet mouse will be as old as his owner was four years ago. Their present ages total 13 years. Find the age of
each now.

owner = 10 years old

mouse = 3 years old

Step-by-step explanation:

Let's say the mouse is currently m years old and the owner is currently o years old.

m + o = 13

In three years, a pet mouse (m+3) will be as old (=) as his owner was 4 years ago (o-4)

m+o=13

m+3=o-4

subtract o from both sides in the first equation to solve for m

m = 13 - o

plug 13-o for m in the second equation to isolate one variable in one equation

13-o+3=o-4

16-o=o-4

add o to both sides to put all the variables on one side

16=2o-4

add 4 to both sides to isolate the variable and its coefficient

20 = 2o

divide both sides by 2 to isolate o

o = 10

m = 13 - o

m = 3

i think the answer is d im not sure