Five years ago, the average age of A, B, C and D was 45 yr. with E joining them now, the average of all the five is 42 yr. How old is E?  Choose the correct choice from the following:
A) 10 yr
B) 40 yr
C) 45yr
D) 64 yr
E) NOne
Solution:   Total present age of A, B, C and D,   = (45*4)+(4*5)= 
<gadget id="calculator">(45*4)+(4*5)</gadget>
<output>200</output>
200 yr;   Total age present age of A, B, C, D and E,= 42*5= 
<gadget id="calculator">42*5</gadget>
<output>210</output>
210 yr.   So, age of E= 10 yr.   10 yrnswer: Option 10 yr
<result>A</result>
Five years ago, the average age of A, B, C and D was 45 yr. with E joining them now, the average of all the five is 42 yr. How old is E?