Answer:
There were 35 gallons of gasoline and 500 gallons of kerosene.
Step-by-step explanation:
<u>Step 1: Write data for equation 1</u>
<em>Let gallons of kerosene be x</em>
<em>Let gallons of gasoline be y</em>
<em>Total capacity of truck is 4000</em>
<u>Step 2: Form equation 1</u>
x + y = 4000
<u>Step 3: Write data for equation 2</u>
<em>Profit of total gallons of kerosene is 0.12x</em>
<em>Profit of total gallons of gasoline is 16y</em>
<em>Total profit is $620</em>
<u>Step 4: Form equation 2</u>
0.12x + 16y = 620
<u>Step 5: Find x in terms of y from equation 1</u>
x + y = 4000
x = 4000 - y
<u>Step 6: Substitute value of x in equation 2</u>
0.12x + 16y = 620
0.12 (4000 - y) + 16y = 620
480 - 12y + 16y = 620
4y = 620 - 480
y = 140/4
y = 35
<u>Step 7: Substitute value of y in equation 1 to find x</u>
0.12x + 16y = 620
0.12x + 16 ( 35 ) = 620
0.12x = 60
x = 500
There were 35 gallons of gasoline and 500 gallons of kerosene.
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