# Maths

posted by
**Remy**
.

When the first n positive integers are added together, their sum is given by

1/2n(n+1)

Find the value of n for which the sum is 105..

Can you show me a step by step please?

posted by
**Remy**
.

When the first n positive integers are added together, their sum is given by

1/2n(n+1)

Find the value of n for which the sum is 105..

Can you show me a step by step please?