Answer :
First of all, let's call Ajani's age A and Steven's age S.
If Ajani's age is 1/3 of Steven's, then we can form the following equation:
[tex]A=\frac{1}{3}S[/tex]This is our first equation. Now we need the second one, which is from the part which says: In 5 years (refers to addition), Ajani will be 1/2 Steven's age, that would mean:
[tex]A+5=\frac{1}{2}(S+5)[/tex]Notice how we use the addition to state the 5 years in the future.
Then, we substitute the first equation into the second one:
[tex]\frac{1}{3}S+5=\frac{S}{2}+\frac{5}{2}[/tex]Now, we solve the equation for S using basic algebra to get:
[tex]\text{S}=15[/tex]Therefore, the right answer is F, that is, Steven's age today is 15