Answer:B
Explanation:
Let, 1st force = a
2nd force = b
A.T.Q,
a+b = 10
a-b = 6
Calculate for a & b, you'll get a=8 & b= 2
After increasing by 3, it'll be a = 8+3 = 11 & b=2+3 = 5
Resultant force at 90 degree angle = 11+5 = 16 Newtons