Question 957136
let hammers be {{{H}}} and saws {{{S}}}
 if hammers and saws  ratio is {{{4:7}}}, then we have
{{{H:S=4:7}}}

If they ordered {{{12}}} hammers, then

{{{12:S=4:7}}}. ...solve for  {{{S}}}

{{{4S=7*12}}}

{{{S=(7*12)/4}}}

{{{S=(7*cross(12)3)/cross(4)1}}}

{{{S=7*3}}}

{{{S=21}}} => the number of saws that were ordered

check the ratio:

{{{H:S=4:7}}}

{{{12:21=4:7}}}
{{{12/21=4/7}}}

{{{cross(12)4/cross(21)7=4/7}}}

{{{4/7=4/7}}}