Re-post from General - FAA Question

[killbilly]

Reposting from General. Should have posted it here, but wasn't sure.

Okay, I've run into this question 2X on two different tests, and I keep getting the answer wrong, which means a) I'm doing it incorrectly or b) the answer to the question is wrong.

So I'm posting the question, and I want to see what you guys come up with. If you could tell me how you come up with the answer, I would appreciate it, because I'm apparently lacking something in my studies and feeling silly. Thanks in advance.

"On a cross-country flight, point A is crossed at 1500 hrs and the plan is to reach point B at 1530 hours. Use the following information to determine the indicated airspeed required to reach point B on schedule:"

Distance between A and B: 70NM
Forecast Wind : 310 at 15
Pressure Alt: 8,000 ft
Ambient Temp: -10C
True Course: 270

The approximate required indicated airspeed would be: ???"

I believe I've been getting it wrong because I'm running the wrong calcs on the E6B.

The way I'm reading it, I need to go 70NM in 30 minutes, which means a GS of 140kts. From there, I take the GS and correct for wind and pressure/temp, right?

Help!

 

[exleardriver]

70 nm in 30 minutes...you say the gs should be 140 kts. i've had too much bourbon tonight and made me go to my car formy e6b, but i think if you mark the wind at 15 from 310, and then slide the card so that the grommet is under 140, i get a tas of 151 kts. on the other side of the e6b, setting -10 degrees celsius over 8000', i read a tas of 151 kts on the outer scale reads a cas of 135 on the inner scale. is this an answer on the test? basically, a cas or ias of 135 kts should yield a tas of 151 kts. at that temp. and altitude. that tas yields a gs of 140 kts. under those wind conditions. you would also correct 3-4 degrees to the right for that northwesterly wind. i don't have my reading glasses..that's as close as i can read that.