First, find the number of females in the class. 
Then, just write the ratio. 
Answer:
last option is correct answer
Step-by-step explanation:
X = 15
X + 90 = 7x
X = 7x - 90
X - 7x = -90
-6x = 90
Divide both sides by -6
X = 15
1.
Chance of finding a bug = 0.35
Chance of not finding a bug = 1 - 0.35 = 0.65
Probability of finding a bug in the first 3 programs =
Probability of not finding a bug in 2 out of the 3 and finding a bug in 1.:
0.65^2 * 0.35 = 0.147 = 0.15
Answer is A.
2.
Probability of heads = 0.50
Probability of tails = 0.50
Probability of heads on the fourth attempt = tails x tails x tails x heads = 0.5 x 0.5 x 0.5 x 0.5 = 0.0625
The answer is B.
w = mg
w/m = g
69N / 12kg = 5.75 N/kg
<u>Answer: B) 5.75 m/s2</u>
