J = 2s
(J+2) + (s+2) = 2s + 2 + s + 2 = 3s + 4 = 43
Solve for s.
Joy's sister is half old as she. In two years, the sum of their ages is 43. How old is Joy's sister?
2 answers
J = Joy's age
S = Sisters's age
Joy's sister is half old as she means:
S = J / 2
After 2 years Joy wil be J + 2 years old, Sister will be S + 2 years old
In two years, the sum of their ages is 43 means:
J + 2 + S + 2 = 43
Now:
J + S + 4 = 43
Subtract 4 to both sides
J + S = 39
Replace S with J / 2 in this equation
J + J / 2 = 39
2 J / 2 + J / 2 = 39
3 J / 2 = 39
Multiply both sides by 2
3 J = 78
J = 78 / 3
J = 26
Joy is 26 yrs old
S = J / 2 = 26 / 2 = 13
Sister is 13 yrs old
S = Sisters's age
Joy's sister is half old as she means:
S = J / 2
After 2 years Joy wil be J + 2 years old, Sister will be S + 2 years old
In two years, the sum of their ages is 43 means:
J + 2 + S + 2 = 43
Now:
J + S + 4 = 43
Subtract 4 to both sides
J + S = 39
Replace S with J / 2 in this equation
J + J / 2 = 39
2 J / 2 + J / 2 = 39
3 J / 2 = 39
Multiply both sides by 2
3 J = 78
J = 78 / 3
J = 26
Joy is 26 yrs old
S = J / 2 = 26 / 2 = 13
Sister is 13 yrs old