30 kg of mocha coffee bean and 20 kg of java coffee bean should be used to make 50 kg of mocha java blend that will sell for $ 18 per kg
<em><u>Solution:</u></em>
Let "x" be the kilogram of mocha coffee beans
Let "y" be the kilogram of java coffee beans
Cost of 1 kg of mocha coffee bean = $ 20
Cost of 1 kg of java coffee bean = $ 15
Kilograms of each kind of coffee bean should he use to make 50 kg of the mocha-java blend
Cost of 1 kg of mocha java blend = $ 18
From given information,
Mocha coffee beans and java coffee beans are mixed to get 50 kg of blend
Therefore,

Abdul wants to make a mocha-java blend that will sell for $18/kg
<em><u>Therefore, we frame a equation as:</u></em>
(kilogram of mocha coffee beans) x (Cost of 1 kg of mocha coffee bean) + (kilogram of java coffee beans) x (Cost of 1 kg of java coffee bean) = Cost of 1 kg of mocha java blend x 50 kg
Thus we get,

<em><u>Let us solve eqn 1 and eqn 2</u></em>
<em><u>From eqn 1,</u></em>
x = 50 - y -------- eqn 3
<em><u>Substitute eqn 3 in eqn 2</u></em>
20(50 - y) + 15y = 900
1000 - 20y + 15y = 900
5y = 100
<h3>y = 20</h3>
<em><u>Substitute y = 20 in eqn 3</u></em>
x = 50 - 20
<h3>x = 30</h3>
Thus 30 kg of mocha coffee bean and 20 kg of java coffee bean should be used to make 50 kg of mocha java blend that will sell for $ 18 per kg