The average of four numbers is 40. If the first number is one-third of the sum of the remaining numbers, then the first number is:
Answer & explanation
Correct answer: option 4
Average of four numbers = 40
Sum of 4 numbers = 40 x 4 = 160
Let first number = A
According to question ,
A = \(\frac{1}{3}\) x Sum of last three numbers
\(\frac{1}{3}\) x Sum of last three numbers + Sum of last three numbers = 160
\(\frac{4}{3}\) x Sum of last three numbers = 160
Sum of last three numbers = 120
So, First number = \(\frac{1}{3}\) x 120
= 40