Question

On Serena’s tenth birthday her mom was 3 tines Serena’s age.how old will Serena and her mom be when her Moms age 0.5 will equal Serena’s age

Answer 1

Mom is 30 years old when Serena is 10 because 10 x 3 = 30.
They are 20 years apart. [This is key]
Half (.5) of mom's age will be = to Serena's age.

Therefore, when mom is 40 years old, Serena is 20 years old.
We can see that half of 40 = 20. 

Hope this makes sense!