The average earning of a mechanic for the first-four days of a week is Rs. 18 and for the last four days is Rs. 22. If he earns Rs . 20 on the fourth day, his average earning for the whole week is ?
Choose one
A) Rs . 18.95 B) Rs 16 C) Rs. 20 D) Rs. 25.71 E) None of these
Answer   Total earning for the week = Sum of earning of first four days + Sum of earning of last four days - Earning of 4th day   = 4 x18 + 4 x 22 -20   = Rs. 140   ∴ Average earning = 140 / 7   = Rs. 20   Rs. 20orrect Option: Rs. 20
<result>C</result>
The average earning of a mechanic for the first-four days of a week is Rs. 18 and for the last four days is Rs. 22. If he earns Rs . 20 on the fourth day, his average earning for the whole week is ?