Question

Of the four numbers, whose average is 60, the first number is the sum of the last 3 numbers. Find the first number

• A. 45
• B. 50
• C. 60
• D. 40
• E. None of the above

Answer 1

The correct option is D 40

Let the 4 numbers be a, b, c and d. $a=\frac{b+c+d}{4}a+b+c+d=\frac{b+c+d}{4}+b+c+d=\frac{5}{4}(b+c+d)=200a=\frac{b+c+d}{4}=\frac{200}{5}=40$