Question 53

Of the 5 numbers whose average is 72, the ﬁrst is 1/8 times the sum of other 4. The ﬁrst number is .---------------

Solution

Let the first number be $$x$$ and sum of other four numbers be $$y$$

=> Average of five numbers = $$\frac{x + y}{5} = 72$$

=> $$x + y = 72 \times 5 = 360$$ ------------(i)

According to ques, => $$x = \frac{1}{8} \times y$$

=> $$y = 8x$$

Substituting value of $$y$$ in equation (i), we get :

=> $$x + 8x = 360$$

=> $$x = \frac{360}{9} = 40$$

=> Ans - (C)

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