1370 , X, 1070 , -180, -6430	Choose the correct choice from the following answers.
A) 1320	B) 6530	C) 6630	D) 6730	E) 6830

Rationale: 1370 - 50 * ( 5 ^ 0 ) = 1320 1320 - 50 * ( 5 ^ 1 ) = 1070 1070 - 50 * ( 5 ^ 2 ) = - 180 - 180 - 50 * ( 5 ^ 3 ) = - 6430 answer : a .
Answer: A