Inequalities

Question

Lexi has $570 in her savings account. She decides to save $20 each month. How many months, m, will it take her to have more than $1000 in her savings account?

 

Answer 1

Hi Rida ,

 

Lexi has $570 in her savings account. To have $1000 in her account Lexi would need (1000 - 570) = $430 more.

 

If Lexi saves $20 each month ,

so Lexi saves $20 after end of 1 month 

                     $40 after end of 2 months

and so on.

 

So $430 is saved after 430 / 20 = 21.5 months, which means that after 21 months Lexi has $420 by saving 20$ each month. Adding another 20 $ in the 22nd month, Lexi will have more than $430 added to her savings.

 

So m = 22 months.