Chapter 11.5, Problem 22WE

To determine

To calculate:

Sum of the positive two-integers ending in $4$ .

Answer to Problem 22WE

Sum of the positive two-integers ending in $4$ is $486$ .

Explanation of Solution

Give information:

The positive two-integers ending in $4$ .

Calculation:

Given is The positive two-integers ending in $4$ ,

The sum is $14+24+\mathrm{...}+94$

Using the formula for the sum of an arithmetic series,

  $\frac{n\left(t_1+t_n\right)}{2}$

This is an arithmetic series with $t_1=14,t_n=94,n=9$

Putting the values in above equation,

  $\begin{array}{l}=\frac{n\left(t_1+t_n\right)}{2}\\ =\frac{9\left(14+94\right)}{2}\\ =\frac{972}{2}\\ =486\end{array}$

Therefore, Sum of the positive two-integers ending in $4$ is $486$ .