Question 13076
This is just a bit of practice in converting the words into algebraic statements. Take them slowly.
Let's call the angles FA, SA, and TA (first angle, second angle, third angle).
The FA is equal to some degrees. Call it x.
So, FA=x. Simple.
The second angle is 10 less than twice the first. Well, twice the first is 2FA and 10 less than THAT would be 2FA - 10.
So, SA = 2FA - 10. Simple again.
The third angle is 25 more than the second.
So, TA = SA + 25. Still simple.
The hard part (?) is getting everything in terms of x.
Look at SA = 2FA - 10. See FA? Well, we know it is equal to x (because we said so). Then SA = 2x - 10. See why?
Now look at TA. It's SA + 25. But SA is 2x - 10. 
So, TA = 2x - 10 + 25. What we now have is
FA = x
SA = 2x - 10
TA = 2x + 15 [I did the math]
And lastly, we know that x + 2x - 10 + 2x + 15 = 180! [Sum of the angles]
Can you simplify that equation to find x?
[You should get an answer that x = 35.]
Then calculate the other angles using the value you found for x.