Hi, there. I'm happy to help with this.
Prompt:
How far in miles is city A from city B?
Because these variables will arise, I will introduce
AB = distance from A to B (what the prompt asks for)
AC = distance from A to C
BC = distance form B to C
Statement #1(1) City A is 50 miles away from city C, whereas city B is 30 miles away from city C.
AC = 50 and BC = 30. No information at all given about AB. Statement #1 is
insufficient.
Statement #2(2) City A is 10 more miles far from city C as it is from city B.
(AC) = 10 + (AB)
Here, if we knew (AC), we could find (AB). With only statement #2, though, we don't know anything else. Therefore, statement #2 is
insufficient.
Combined Statements #1 & #2(1) City A is 50 miles away from city C, whereas city B is 30 miles away from city C.
(2) City A is 10 more miles far from city C as it is from city B.
In algebraic form
AC = 50, BC = 30, and (AC) = 10 + (AB)
===> 50 = 10 + (AB) ===> AB = 40
Thus, combining the statements, we are able to determine precisely a numerical answer to the prompt.
Answer = C I believe santu71182 and kys123 are quite correct
Notice, BTW, the three cities form a 3-4-5 right triangle --- a geometrically convenient but geographically unlikely formation.
Here's another free geometry DS question, for more practice.
https://gmat.magoosh.com/questions/1019Does everything I've said make sense? Please let me know if you have any questions.
Mike
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Mike McGarry
Magoosh Test Prep