The average age of a couple was 24 years. After their 1st and 2nd children (twins) were born, the average age of the family became 13.5 years. The average age of the family just after 3rd child was born was 13.2 years. The average age of the family after 4th child was born was 16 years. The current average age of the family is 19 years. What is the current age of the twin children? Pick.
A) 14 years
B) 15 years
C) 11 years
D) 12 years
E) 10 years
DETAILED SOLUTION   Sum of the ages of the couple = 24 * 2= 
<gadget id="calculator">24 * 2</gadget>
<output>48</output>
48   After the 1st and 2nd children, sum= 13.5 * 4= 
<gadget id="calculator">13.5 * 4</gadget>
<output>54</output>
54   Difference in sum= 54 – 48 = 6 years   Or after 6/ 2= 
<gadget id="calculator">6/ 2</gadget>
<output>3</output>
3 years, the twin were born to the couple (Ages of children at the time of birth is 0)   After 3rd child, sum= 13.2 * 5= 
<gadget id="calculator">13.2 * 5</gadget>
<output>66</output>
66 yrs   Difference= 66 – 54 = 12   Or after 12/4= 
<gadget id="calculator">12/4</gadget>
<output>3</output>
3 yrs, 3rd child was born (Couple + 2 children were already present. So 4)   After 4th child, sum= 16 * 6= 
<gadget id="calculator">16 * 6</gadget>
<output>96</output>
96 yrs   12 yearsifference= 96 – 66 = 30   Or after 30/5= 
<gadget id="calculator">30/5</gadget>
<output>6</output>
6 yrs, 4th child was born   Current sum= 19 * 6= 
<gadget id="calculator">19 * 6</gadget>
<output>114</output>
114 yrs   12 yearsifference 114 – 96= 18 yrs   Or after  18/6= 
<gadget id="calculator"> 18/6</gadget>
<output>3</output>
3 yrs   The gap between the children are as follows: 3 yrs, 6 yrs and 3 yrs   Age of eldest ones= 3 + 6 + 3= 
<gadget id="calculator">3 + 6 + 3</gadget>
<output>12</output>
12   Correct Answer: 12 years
<result>D</result>
The average age of a couple was 24 years. After their 1st and 2nd children (twins) were born, the average age of the family became 13.5 years. The average age of the family just after 3rd child was born was 13.2 years. The average age of the family after 4th child was born was 16 years. The current average age of the family is 19 years. What is the current age of the twin children?