Question

A student saves $3 dollars on August 1, $5 on August 2, $7 on August 3, and so on. How much will she save in August 20 ?

Answer 1

Here is your answer

Money saved on each successive day is-

$3, &5, $7....

Clearly it forms an AP,

where

a1= 3

common difference, d= 2

n=20

So,

using formula

Tn= a1+(n-1)d

T20= 3+(20-1)2

= 3+ 19×2

= 3+ 38

=41

So, money saved on August 20= $41

Sum of money saved upto August 20 =
n/2 (a1+T20)
= 20/2 (3+41)
= 10× 44
= $440

HOPE IT IS USEFUL

Answer 2

$41. It increases by $2 each day. Formula 2n+1 :)