Answer:
B 20
Step-by-step explanation:
Procedure:
1) calculate the number of diferent teams of four members that can be formed (with the ten persons)
2) calculate the number of teams tha meet the specification (two girls and two boys)
3) Divide the positive events by the total number of events: this is the result of 2) by the result in 1)
Solution
1) the number of teams of four members that can be formed are:
10*9*8*7 / (4*3*2*1) = 210
2) Number of different teams with 2 boys and 2 girls = ways of chosing 2 boys * ways of chosing 2 girls
Ways of chosing 2 boys = 6*5/2 = 15
Ways of chosing 2 girls = 4*3/2 = 6
Number of different teams with 2 boys and 2 girls = 15 * 6 = 90
3) probability of choosing one of the 90 teams formed by 2 boys and 2 girls:
90/210 = 3/7
Since a is supplementary to b, their sum is 180*.
m55+b=180
-55 -55
b=125*
Answer: 216 millilitres
Step-by-step explanation:
From the question, you are given that there are 3 milliliters of compound A used for every 5 milliliters of compound B. That means compound A and B are in ratio 3 to 5. That is,
A : B = 3 : 5
If a chemist wants to make 576 milliliters of the drug, then find the ratio of compound A.
To do that, first add the ratio of both together, 3 + 5 = 8
For compound A,
3/8 × 576
1728/8 = 216 millilitres
Therefore, 216 millilitres of compound A are needed.