A customer purchased an electronic device for 650. Each year the value of the electronic device decreases by 30%. Which statement is true about the graph that represents the relationship between the value of the device in dollars, y, and the number of years, x , since the device was purchased?

解

A c u s t o m er p u rc ha se d an e l ec t ro ni c d e v i ce f or 650. E a c h ye a r t h e v a l u e o f t h e e l ec t ro ni c d e v i ce d ecre a ses b y 30%. Whi c h s t a t e m e n t i s t r u e ab o u t t h e g r a p h t ha t re p rese n t s t h e re l a t i o n s hi p b e tw ee n t h e v a l u e o f t h e d e v i ce in d o ll a rs, y, an d t h e n u mb er o f ye a rs, x, s in ce t h e d e v i ce w a s p u rc ha se d ?

Amount before reduction : 928.57142 \dots

解答ステップ

Translate the problem into an equation:

650 = x - 0.3 x

650 = x - 0.3 x : x = \frac{6500}{7}

\frac{6500}{7} = 928.57142 \dots

Amount before reduction : 928.57142 \dots