Two twins sisters Sita and Geeta were standing back to back and suddenly they started running in opposite directions for 10 km each. Then they turned left and ran for another 7.5 km.
What is the distance (in kilometers) between the the two twins when they stop?	Pick
A) 21 B) 23 C) 25 D) 27 E) 30

Rationale: the distance between them is the hypotenuse of a right angle triangle with sides 15 km and 20 km . the hypotenuse = sqrt ( 15 ^ 2 + 20 ^ 2 ) = 25 the answer is c .
Answer: C