Question 182236
Let {{{a}}} = amount of 238 iodine needed
Let {{{b}}} = amount of 691 iodine needed
given:
{{{b = 55}}}oz
{{{.53a + 2.35b = .77*(a + b)}}}
{{{.53a + 2.35*55 = .77*(a + 55)}}}
{{{.53a + 129.25 = .77a + 42.35)}}}
{{{.53a + 129.25 = .77a + 42.35)}}}
{{{.24a = 86.9}}}
{{{a = 362.1}}} oz
She needs 362.1 oz of the 238 iodine
check:
{{{.53a + 2.35b = .77*(a + b)}}}
{{{.53*362.1 + 2.35*55 = .77*(362.1 + 55)}}}
{{{191.9 + 129.25 = 321.2}}}
{{{321.2 = 321.2}}}
OK