Concept: The Question tests on the application of summation formula and concept associated.

Solution:
 
A NEW OG 2021 QUESTION

In the first week, the amount saved = 1$

Money saved by the end of 2 weeks = 1$ + 2$

Money saved by the end of 3 weeks = 1$ +2$ + 3$

..In the same pattern, the money saved by the end of 50th week

= 1$ + 2$ +3$ +......50$

= (50* 51)/2 (The sum of 1+2+3+4+..n= n(n+1)/2 )

= 1275$

Total money saved by him in his account

= 800$ (saved previously) + 1275$

= 2075$ (OPTION D)