Question 888084
Nickels and dimes cannot make $1.74; but they can make $1.75.


{{{0.05n+0.1d>=1.75}}} and {{{n+d=30}}}.  You want the inequality to be expressed only in dimes.


{{{n=30-d}}}; substitute this.
{{{0.05(30-d)+0.1d>=1.75}}}
Divide members by 0.05.
{{{30-d+2d>=35}}}
{{{30+d>=35}}}
{{{highlight(d>=5)}}}.


Many values of d will give at least $1.75, but the smallest is {{{highlight(highlight(d=5))}}}.