Question 270054
{{{a}}} = number of adult tickets sold
{{{c}}} = number of children's tickets sold
given:
(1) {{{a + c = 150}}}
(2) {{{20a + 10c = 2470}}}
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Subtract (1) from (2)
(2) {{{2a + c = 247}}}
(1) {{{-a - c = -150}}}
{{{a = 97}}}
97 adult tickets were sold
check answer:
and from (1),
{{{97 + c = 150}}}
{{{c = 150 - 97}}}
{{{c = 53}}}
and
(2) {{{20a + 10c = 2470}}}
{{{20*97 + 10*53 = 2470}}}
{{{1940 + 530 = 2470}}}
{{{2470 = 2470}}}
OK