The perimeter of an equilateral triangle is 60. If one of the sides of the equilateral triangle is the side of an isosceles triangle of perimeter 65, then how long is the base of isosceles triangle? Choose the correct choice from the following answers:
A) 10 B) 15 C) 20 D) 25 E) 30
The base of the isosceles triangle is 65-20-20= 
<gadget id="calculator">65-20-20</gadget>
<output>25</output>
25 units   The answer is 25.
<result>D</result>
The perimeter of an equilateral triangle is 60. If one of the sides of the equilateral triangle is the side of an isosceles triangle of perimeter 65, then how long is the base of isosceles triangle?