Answer:
28 students
Step-by-step explanation:
Let number of students in cooking club = x
Number of students in fencing club = 1/5 x
Number of students in chess club = 2(1/5)x
Since, There are 42 more students in the cooking club than in the chess club
Then ;
Number of students in chess club = Number of students in cooking club - 42
2(1/5)x = x - 42
(2/5)x - x = - 42
(2/5)x - x = - 42
-0.6x = - 42
x = 42 / 0.6
x = 70
Hence, number of students in chess club :
(2/5) * 70 = 28
Here is the equation:

Since both decimals are negative, the answer will be positive.
- Negative times Negative = Positive
Divide both sides by -3.9 to leave the variable alone:

r is equal to 4 → r = 4
Answer: 20 mph
Explanation:
Speed is a physical quantity which is equal to the ratio between the distance covered (d) and the time taken (t):

In the first part of the problem, the plane flew a distance of d=400 mi in a time of t=2.5 h. The speed of the plane in this case was the difference between the proper speed of the plane, v, and the speed of the wind, w, since the plane flew opposite to the wind. So we can write:
(1)
During the return trip, the plane flew with a speed (v+w), since the wind was on the tail, and it took 2 hours to cover the same distance:
(2)
So we have two equations with two unknown variables. From (1), we get

Substituting into eq.(2)

So, the speed of the wind was 20 mph.
Answer:
cos(2sin−1x)=1−2x2
Step-by-step explanation:
et sin−1x=θ , so that, x=sinθ,|x|≤1,θ∈[−π2,π2].
The probability is likely but not impossible. there is a 4/5 chance she will not spend a four.