Question 413981
Let {{{a}}} = weight of large box in pounds
Let {{{b}}} = weight of small box in pounds
given:
(1) {{{70a + 55b = 4250}}}
(2) {{{a + b = 65}}}
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Multiply both sides of (2) by {{{55}}} and
subtract from (1)
(1) {{{70a + 55b = 4250}}}
(2) {{{-55a - 55b = -3575}}}
{{{15a = 675}}}
{{{a = 45}}}
and
(2) {{{45 + b = 65}}}
{{{b = 20}}}
A large box weighs 45 pounds
A small box weighs 20 pounds
check answer:
(1) {{{70a + 55b = 4250}}}
(1) {{{70*45 + 55*20 = 4250}}}
{{{3150 + 1100 = 4250}}}
{{{4250 = 4250}}}
OK