Carlos is planting a lemon tree. The tree will cost $90 to plant. Each year it will grow 7 lemons, which he can sell for $1.5 each. It costs $3 a year to water and feed the tree. How many years will it take before he starts earning money on the lemon tree?
He makes $10.5 selling lemons each year because 7 x 1.5 = 
<gadget id="calculator">7*1.5</gadget>
<output>10.5</output>
10.5.
He earns $7.5 each year from the lemon tree because 10.5 - 3 = 
<gadget id="calculator">10.5-3</gadget>
<output>7.5</output>
7.5.
It will take 12 years to earn enough to pay off the tree because 90 / 7.5 = 
<gadget id="calculator">90/7.5</gadget>
<output>12</output>
12.
He will make money in year 13 because 12 + 1 = 
<gadget id="calculator">12+1</gadget>
<output>13</output>
13.

<result>13</result>