How should I exercise to develop a six pack + upper body strength?
Hey, I am 17 and I weigh about 112 pounds and I am about 5’7.
I would like to know what exercises are recommended to develop a six pack and upper body strength and how often I should do these exercises. I would also like to know about what my diet should be during this.
Thanks.

You need to have right info if you want to lose weight. You can tried method that I lost 16 pounds in 55 days. It works amazing and It will work for you too. You can get more info here link below.
To get cut you need to lose fat, and your already skinny. So Weight lift to build strength and cardio to burn fat.
Go check out http://www.ivannikolov.com/ or any other bodybuilding site. there’s tons of Information out there for you.
start off like that .
1st month
1st week : monday : biceps and triceps curl 4 sets ( 10 , 12 , 10 , 12 )[start off with 5 or 6 kg]
tuesday : sit ups & rest ( 60 sit ups ) 3 sets , 20 per set.
wednesday : biceps and triceps curl . (same )
thursday: chest building ( push ups ) triangle push ups . start of with 30 times. 10 per set
friday : biceps and triceps curl (same)
saturday : push ups and sit ups. (same)
sunday : biceps and triceps (same)
2nd week : same
3rd week : same
4th week : increase weight to 7kg. add 1 more set to push ups and sit ups
2nd month :
1st week : same
2nd week : same
3rd week : increase weight to 8 / 9 kg. add 1 more set to push ups and sit up
4th week : you should see some difference .
3rd month :
1st week : same
2nd week : same
3rd week : increase weight to 10 kg . same number of push ups and sit ups.
4th week : same
continue doing what you’re doing. number of push ups and sit ups depends on yourself. if you find it easy , increase slowly. 1 set in 3 weeks maybe? dumbbells too. max – 15 kg. dont go overboard.
Food : Morning : Protein shake . / Milk / Wheatbix with yogurt / 2 hard boiled eggs
Afternoon : RICE with PROTEIN ( Fish , CHICKEN , Meat , Ham ..etc.)
Night : PROTEIN .
eat lots and lots of protein. for your size , try eating 5000 calories a day.
MOST IMPORTANTLY. Do not over workout. muscles grow when you’re resting. HAVE 8 HOURS OF SLEEP EVERYDAY. 8 ! muscles grow when you’re sleeping too .
Good luck , all the best (: