Question

Let N be a positive integer where N<=2021. The numbers 1 to N are written in row.We erase two consecutive numbers replacing them with either their sum or product.What's the sum of all posibble values of N so that the last single number is always odd?​

Answer 1

Step-by-step explanation:

Let N be a positive integer where N<=2021. The numbers 1 to N are written in row.We erase two consecutive numbers replacing them with either their sum or product.What's the sum of all posibble values of N so that the last single number is always odd?

sry I don't know answer

Answer 2

Easier way would be using sum of all n even integers = n * (n+1)

for example

Hence from 1-301 there are 150 even integers hence sum = 150 * 151 = 22650

From 1- 99 there are 49 even integers ( - 1 as 100 is not part of this) = 49 * 50 = 2450

So sum from 99-301 = 22650 -2450 = 20200