Answer:
12
Step-by-step explanation:
Givens
Harpreet        = x + 3 
Sukhpreet     = x
Komalpreet   = 2*(x + 3)
 Average Age = 15
Equation
[(x + 3) + x + 2*(x + 3) ] / 3 = 15                  Multiply both sides by 3
Solution
3 [(x + 3) + x + 2*(x + 3) ] / 3 = 15 * 3         Combine
  [(x + 3) + x + 2*(x + 3) ]       =   45             Remove the brackets
x + 3 + x + 2x + 6                 =   45             Combine like terms
4x + 9 = 45                                                 Subtract 9 from both sides
4x + 9 - 9 = 45 - 9                                       Combine
4x = 36                                                         Divide by 4
4x/4 = 36/4
x = 9
Answer
Harpreet is  x+ 3 = 9 + 3 = 12 
 
        
             
        
        
        
<h3>
Answer: C) nonmetal</h3>
This element has 8 protons, so element is oxygen. I recommend looking at the periodic table of elements. At standard temperature and pressure (STP), oxygen is a gas, so that puts it in the nonmetal category. 
Side note: Metalloids are a collection of elements where they share properties of metals and nonmetals (in a way they're on the fence). 
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
surface area of sphere=a
4pir^2=a
r^2=a/4p
r=root(a/4pi)
if radius is doubled
r1=2root(a/4pi)
r1^2=4(a/4pi)
a/a1=(4pia/4pi)/(4pi 4a/4pi)=1/4
so a is increased by 4 times