Answer
4 and 7 nickles
Work Step by Step
Consider the inequality $3.2 \leq 0.1d +0.25 q+0.05 n\leq 5.45$
This implies that
$3.2 \leq 0.1(2x-3) +0.25(2x+2)+0.05x\leq 5.45$
or, $3.2 \leq 0.2x-0.3 +0.5x+0.5+0.05x\leq 5.45$
or, $3.2 \leq 0.75x+0.2\leq 5.45$
or, $3.2-0.2 \leq 0.75x\leq 5.45-0.2$
Hence, $4 \leq x\leq 7$, that is, 4 and 7 nickles
