Q. The average length of first 3 fingers is 3 inches and the average length of the other 2 fingers viz. thumb and the index finger is 2.8 inches. If the length of the index fingers is 3 inches then what is the length of the thumb?
Answer: 2.6 inches
Notes: The average length of the thumb and index finger is 2.8 and the length of index finger is 3 inches. The total length of index finger and thumb =2.8×2=5.6 inches. Thus the length of thumb is (5.6-3)=2.6 inches.