Solution:
Angles EBC and ABE are adjacent and form a straight line.
Therefore, ∠EBC plus ∠ABE equals 180 degrees.
Expressed as: 3r + 10 plus 2r - 20 equals 180.
Simplifying gives 5r minus 10 equals 180.
Adding 10 to both sides, 5r equals 190.
Dividing both sides by 5 results in r equals 38.
Next, substitute the value of r.
Given that ∠EBF equals ∠ABE,
∠EBF equals 2r minus 20.
Plugging in r = 38: ∠EBF = 2 × 38 minus 20.
Which simplifies to 76 minus 20,
Hence, ∠EBF is 56 degrees (Final answer).
