At point A
The pressure according to ideal gas equation is $P_A = C_ART_A$. Here $C_A (= n/V)$ is concentration at A.
At point B
Similarly, the pressure according to ideal gas equation is $P_B = C_BRT_B$. Here again $C_B$ is concentration at B.
Now, $P_A$ > $P_B$
So, $C_ART_A$ > $C_BRT_B$
i.e. $C_A/C_B$ > $T_B/T_A$ .....equation 1
Now as the condition is that concentration at A is lower than the the concentration at B. Therefore we can say that
$C_A/C_B$ < $1$ .....equation 2
Now from equation 1 and 2 we have
$T_B/T_A$ < $1$
which gives us $T_A$ > $T_B$
So in the end, yes, your book was right. It is possible if the temperature at A is more than that at B.
"HOW TO FIND IT IN SECONDS" or "I HATE TO DERIVE BY USING EQUATIONS"
Think of two containers A and B which are connected by a pipe. Both are connected with the help of a pipe which is closed (i.e. it doesn't let the gases exchange). Now we know that concentration of gas in A is lower than the the concentration of gas in B. If we want more pressure of gas in A then the velocity of its particles should be more. Now it is possible if it has more thermal energy. So the temperature should be more in A.