7 1/4
that is the numerical difference between the two
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
Answer:
6hours
Step-by-step explanation:
From the given information:
Suppose it took Karl x hours to retile her bathroom,
Then it will take Della 3 hours longer i.e (3+x) hours
If Della and Karl work together or will take them 2 hours
The objective is to determine how long it will take Delia to retile the bathroom alone?
∴



By cross multiplying, we have:
2(2x+3) = 3x+x²
4x + 6 = 3x + x²
3x + x² - 4x - 6
x² - x - 6 = 0
Using quadratic equation
x² -3x +2x - 6 = 0
x(x - 3) + 2(x - 3) = 0
(x +2) (x - 3) = 0
x + 2 = 0 or x - 3 = 0
x = -2 or x = 3
Since we are concerned about the positive integer,
Then, Karl = x = 3 hours while Della which is (3+x) = 3+3 = 6hours