Question

Nine members of a family are standing in a row. Their average age is 70. The average age of the first four members in the row is 64 and the average age of the last seven members in the row is 80. What is the average age of the third and fourth member in the row? a) 78 b) 86 c) 93 d) 89

Answer 1

Step-by-step explanation:

The avg. age of 9 members is 70

so s1+ s2 + to s9/ 9= 70 = 70×9 = 630

as the avg. age of last 7 member is 80

80× 7 = 560 now..

630 - 560= 70

which is the combined age of s1 and s2.

as it is giver avg of first 4 members is 64 so the combined age is 256

from which 256 - 70= 186

which is combined age of s3 and s4 so the avg is 186/ 2 = 93.

C IS THE RIGHT ANSWER DEAR ...