### Average of ten positive numbers is x. If each number is increased by 10%, then x :

A. remains unchanged

B. may decrease

C. may increase

D. is increased by 10%

Let 10 numbers be x1, x2, x3, . . . . . . . x10 According to question average of these 10 numbers is 10 $\Rightarrow \Large\frac{x 1+x 2+x 3+\ldots+x 10}{10}=x$ Now if each number is increased by 10%, then new average, say y. $\begin{array}{l}y=\Large\frac{1.1×1+1.1×2+1.1×3+\ldots+1.1×10}{10}\\ \Rightarrow y=1.1\times\Large\frac{x1+x2+x3+\ldots+x10}{10}\\ \Rightarrow y=1.1x\\ \Rightarrow y\text{ is }10\%\text{ increased }\end{array}$