Question 159297
{{{a}}}= number who rented skis
{{{b}}}= number who rented snowboards
Given:
{{{a + b = 28}}}
{{{16a + 19b = 478}}}
Multiply both sides of the 1st equation by {{{16}}} and 
subtract it from the 2nd equation
{{{16a + 19b = 478}}}
{{{-16a - 16b = -448}}}
{{{3b = 30}}}
{{{b = 10}}}
{{{a = 28 - b}}}
{{{a = 28 - 10}}}
{{{a = 18}}}
18 rented skis and 10 rented snowboards
check:
{{{16a + 19b = 478}}}
{{{16*18 + 19*10 = 478}}}
{{{288 + 190 = 478}}}
{{{478 = 478}}}
OK