Inequality problem algebra? How would I solve the following inequality problem.
$s+1<2s+1<4$
My book answer says $s\in (0, \frac32)$ as the final answer but I cannot seem to get that answer.

We have $$s+1<2s+1<4.$$ This means $2s+1<4$, and in particular, $2s<3$. Dividing by the $2$ gives $s<3/2$. Now, observing on the other hand that we have $s+1<2s+1$, we subtract $s+1$ from both sides and have $0<s$. This gives us a bound on both sides of $s$, i.e., $$0<s<\frac{3}{2}$$ as desired.
