Aishwarya’s mom was 20 years of age at the time of her birth, while her mom was 15 years old when her 4 years younger sister was born. The variance between the parents ages is :  Select:
A) 6 years B) 11 years C) 10years D) 9 years E) 4 years
D   9 years   Mom’s age when Aishwarya’s sister was born = 15 years.   Dad’s age when Aishwarya’s sister was born = (20 + 4)= 
<gadget id="calculator">(20 + 4)</gadget>
<output>24</output>
24 years.   Needed Variance= (24 – 15) years = 9 years.   Answer is 9 years
<result>D</result>
Aishwarya’s mom was 20 years of age at the time of her birth, while her mom was 15 years old when her 4 years younger sister was born. The variance between the parents ages is :