Question: Find the Value of Term 10

Comment on Find the Value of Term 10

Hi Brent, wondering if on GMAT can we get a case where 2 statements may give different values of k and we say both are sufficient?

for example the above question itself if we get k=5 in statement 1 and k=10 in statement 2? Will the answer be still D?
gmat-admin's picture

If we solve the equation in statement 2, we get k = 5

Start with: 80k + 150 = 77k + 165
Subtract 150 from both sides: 80k = 77k + 15
Subtract 77k from both sides: 3k = 15
Solve: k = 5

A useful feature of Data Sufficiency questions is that the statements will never contradict each other.

So, for example, you will never find a question in which one statement says x = 3 and the other statement says x = 10

For more on this, watch:


I'm confused as well since statement 2 only tells us the ratio but not the exact value
gmat-admin's picture

If statement 2 (term_8/term_7 = 11/10) were the only piece of information, then we wouldn't be able to determine the value of term_10.
However, the given information also tells us that term_n = kn + 15.

So, from term_2, we can conclude that k = 5 (see the calculations in my response about).
Once we know that k = 5, we can use the fact that term_n = kn + 15.
Replace n with 10 to get: term_10 = k(10) + 15.
Plug k = 5 into the above equation to get: term_10 = 5(10) + 15 = 50 + 15 = 65

Does that help?

Wow, I immediately chose D after reading the question, im surprised I did it correctly, probably because these two statements can be solved too obviously!

Office Hours

Have questions about your preparation or an upcoming test? Need help modifying the Study Plan to meet your unique needs? No problem. Just book a Skype meeting with Brent to discuss these and any other questions you may have. 

Change Playback Speed

You have the option of watching the videos at various speeds (25% faster, 50% faster, etc). To change the playback speed, click the settings icon on the right side of the video status bar.

Have a question about this video?

Post your question in the Comment section below, and a GMAT expert will answer it as fast as humanly possible.

Free “Question of the Day” emails!