Question 398852
There are 2 grams of protein and 25 grams of carbohydrates in 1 serving of Cornies
There are 4 grams of protein and 20 grams of carbohydrates in  1 serving of Oaties.
Let {{{a}}} = number of servings of Cornies needed
Let {{{b}}} = number of servings of Oaties needed
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given:
For protein:
(1) {{{2a + 4b = 24}}}
For carbs:
(2) {{{25a + 20b = 210}}}
Multiply both sides of (1) by {{{5}}}
and subtract (1) from (2)
(2) {{{25a + 20b = 210}}}
(1) {{{-10a - 20b = 120}}}
{{{15a = 90}}}
{{{a = 6}}}
And, from (1),
{{{2*6 + 4b = 24}}}
{{{4b = 12}}}
{{{b = 3}}}
6 servings of Cornies and 3 servings of Oaties are needed
check answer:
For protein:
(1) {{{2a + 4b = 24}}}
(1) {{{2*6 + 4*3 = 24}}}
(1) {{{12 + 12 = 24}}}
OK
For carbs:
(2) {{{25a + 20b = 210}}}
(2) {{{25*6 + 20*3 = 210}}}
(2) {{{150 + 60 = 210}}}
(2) {{{210 = 210}}}
OK