Answer:
Mr.Kim is presently 40 years old, and his daughter is 15 years old.
Step-by-step explanation:
K is Mr Kim's present age
D=his daughter's present age.
K=D+25 ; or Mr.Kim is his daughter's age plus 25 years.
K+10=2(D+10); or in 10 years, Mr Kim will be twice daughters age
Substitute the K from the first equation into the second equation and then solve for variable D.
(D+25)+10 = 2(D+10) Simplify.
D+35 = 2D+20 You must subtract D from both sides.
35 = D+20 Lastly, subtract 20 from both sides.
15 = D or D = 15
Mr Kim's daughter's is 15 years old.
Mr Kim's age is D+25
15+25 = 40 years old.
