Lisa and Robert have taken the same number of photos on their school trip. Lisa has taken 3 times as many photos as Claire and Robert has taken 20 more photos than Claire. How many photos has Claire taken?  Choose the correct choice from the following choices
A) 6	B) 8	C) 10	D) 12	E) 14

Rationale: "l = r l = 3 c r = c + 20 3 c = c + 20 c = 10 the answer is c ."
Answer: C