7c+ 12= -4c+ 78
⇒ 7c+ 4c= 78 -12 (inverse operation)
⇒ 11c= 66
⇒ c= 66/11 (inverse operation)
⇒ c= 6
Final answer: c= 6.
So what we need to do is divide the number of people under 16 by the number of the entire population:

first, let's get rid of the 0s:

now, we can divide:
this is 0.6507....
in order to make this into a percentage, we multiply by 100%:
0.6507*100%=65.07%
the answer is: 65 % (quite a lot!!!)
1/7 x 28 = 4 yellow balls
5/7 x 28 = 20 white balls
28 - (20+4)
= 28 - (24)
= 4
4 of the balls are green
Answer:
a) 3 x 20 = 60
b) -2x20 = -40
question c and d are unclear as we do not know how many questions were wrong and how many were not answered.
Sorry but I hope that helped